U.S. patent number 10,335,055 [Application Number 15/636,549] was granted by the patent office on 2019-07-02 for kinetic assessment and alignment of the muscular-skeletal system and method therefor.
This patent grant is currently assigned to Orthosensor Inc.. The grantee listed for this patent is Orthosensor Inc.. Invention is credited to Martin Roche, Marc Stein.
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United States Patent |
10,335,055 |
Stein , et al. |
July 2, 2019 |
Kinetic assessment and alignment of the muscular-skeletal system
and method therefor
Abstract
A system is disclosed herein for providing a kinetic assessment
and preparation of a prosthetic joint comprising one or more
prosthetic components. The system comprises a prosthetic component
including sensors and circuitry configured to measure load,
position of load, and joint alignment. The system further includes
a remote system for receiving, processing, and displaying
quantitative measurements from the sensors. The kinetic assessment
measures joint alignment under loading that will be similar to that
of a final joint installation. The kinetic assessment can use trial
or permanent prosthetic components. Furthermore, adjustments can be
made to the applied load magnitude, position of load, and joint
alignment by various means to fine-tune an installation. The
kinetic assessment increases both performance and reliability of
the installed joint by reducing error that is introduced by
elements that load or modify the joint dynamics not taken into
account by prior assessment methods.
Inventors: |
Stein; Marc (Chandler, AZ),
Roche; Martin (Fort Lauderdale, FL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Orthosensor Inc. |
Dania Beach |
FL |
US |
|
|
Assignee: |
Orthosensor Inc. (Daina Beach,
FL)
|
Family
ID: |
51530587 |
Appl.
No.: |
15/636,549 |
Filed: |
June 28, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180000380 A1 |
Jan 4, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14026544 |
Sep 13, 2013 |
9820678 |
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61803078 |
Mar 18, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
5/4851 (20130101); A61B 5/686 (20130101); A61B
90/37 (20160201); A61B 5/4571 (20130101); G06F
3/0481 (20130101); A61B 34/10 (20160201); A61B
17/154 (20130101); A61F 2/461 (20130101); A61F
2/4684 (20130101); A61B 5/4585 (20130101); A61F
2/4657 (20130101); A61B 17/157 (20130101); A61B
34/20 (20160201); A61B 5/1072 (20130101); A61B
5/4528 (20130101); A61B 17/155 (20130101); A61B
17/1764 (20130101); A61B 5/45 (20130101); A61F
2/3836 (20130101); A61B 5/1121 (20130101); A61B
34/25 (20160201); A61B 5/103 (20130101); A61B
5/1036 (20130101); A61F 2/38 (20130101); A61B
2034/105 (20160201); A61B 2034/104 (20160201); A61B
2034/102 (20160201); A61F 2002/4658 (20130101); A61F
2002/4668 (20130101); A61B 5/4887 (20130101) |
Current International
Class: |
A61B
5/103 (20060101); A61F 2/46 (20060101); A61B
17/17 (20060101); A61B 5/11 (20060101); A61B
90/00 (20160101); A61B 34/00 (20160101); A61B
34/20 (20160101); A61B 17/15 (20060101); A61B
5/00 (20060101); A61F 2/38 (20060101); A61B
34/10 (20160101); A61B 5/107 (20060101); G06F
3/0481 (20130101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1800097 |
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May 2008 |
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EP |
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2006098759 |
|
Sep 2006 |
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WO |
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2008120215 |
|
Oct 2008 |
|
WO |
|
Primary Examiner: Gibson; Eric S
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Utility patent
application Ser. No. 14/026,544, the disclosure of which is
incorporated herein by reference in its entirety. Furthermore,
application Ser. No. 14/026,544 claims the benefit of provisional
patent application No. 61/803,078 filed 18 Mar. 2013, the
disclosure of which is incorporated herein by reference in its
entirety.
Claims
What is claimed is:
1. An orthopedic measurement system for kinetic assessment
comprising: a device having a surface configured to couple to a
joint of a musculoskeletal system comprising at least one sensor
configured to measure one or more parameters wherein the device
includes a tracking system; a computer configured to receive
measurement data from the at least one sensor and the tracking
system; a display coupled to the computer, wherein the display
includes a graphical user interface, wherein a memory and one or
more processors are configured to execute one or more programs
stored in the memory, wherein the computer is configured to receive
measurement data from the at least one sensor of the device,
wherein the graphical user interface includes a graphical depiction
of a portion of a surface of the device that is configured to
couple to the joint, wherein a contact point is displayed on the
graphical depiction of the portion of the surface of the device,
wherein the computer is configured to use the measurement data to
calculate a contact point location on the graphical depiction of
the portion of the surface of the device, and wherein the contact
point is configured to move in real-time corresponding to movement
of the joint.
2. The system of claim 1 wherein the display is configured to
indicate a predetermined area range on the graphical depiction of
the portion of the surface of the device and wherein the computer
is configured to use the measurement data to calculate if the
contact point is within or outside the predetermined area
range.
3. The system of claim 1 wherein the device comprises: an articular
surface configured to support movement of the joint; and a
plurality of load sensors underlying the articular surface, wherein
a kinetic assessment results in at one least change performed under
musculoskeletal loading that produces a measurement change from the
plurality of load sensors and is reflected in movement of the
contact point on the display.
4. The system of claim 3 wherein the computer is configured to
receive load measurement data from the plurality of load sensors
and wherein the computer is configured to use the load measurement
data from the plurality of load sensors to calculate the contact
point on the display.
5. The system of claim 4 wherein the contact point on the display
is configured to move in response to joint movement, tissue
tensioning, bone cutting, shimming, or other changes that affect
loading on the articular surface.
6. The system of claim 1 wherein the device is a prosthetic
component of the joint.
7. The system of claim 1 wherein the computer is configured to
calculate alignment from the measurement data.
8. The system of claim 1 wherein the display is configured to
indicate a range of the movement of the joint or the device and
wherein the graphical user interface includes a graphical depiction
of at least a portion of the joint, wherein the computer is
configured to track movement of the joint, and wherein the
graphical depiction of the at least a portion of the joint is
configured to move on the display corresponding to actual movement
of the joint.
9. The system of claim 1 wherein the display is configured to
display one of a bone offset relative to a mechanical axis or a
total offset relative to the mechanical axis generated from the
measurement data.
10. An orthopedic measurement system for kinetic assessment
comprising: a prosthetic component of a prosthetic joint comprising
at least one sensor and a tracking system configured to measure a
parameter, wherein the prosthetic component is configured to
measure position, rotation, or slope; a computer configured to
receive measurement data from the at least one sensor and the
tracking system; a display coupled to the computer, wherein the
display includes a graphical user interface, wherein a memory and
one or more processors are configured to execute one or more
programs stored in the memory, wherein the computer is configured
to receive measurement data from the at least one sensor of the
device, wherein the graphical user interface includes a graphical
depiction of a portion of a surface of the prosthetic component
that is configured to couple to the prosthetic joint, wherein a
contact point is displayed on the graphical depiction of the
portion of the surface of the prosthetic component, wherein the
computer is configured to use the measurement data to calculate a
contact point location on the graphical depiction of the portion of
the surface of the device, and wherein the contact point is
configured to move in real-time corresponding to movement of the
prosthetic joint.
11. The system of claim 10 wherein the display is configured to
indicate a predetermined area range on the graphical depiction of
the portion of the surface of the prosthetic component, wherein the
computer is configured to use the measurement data to calculate if
the contact point is within or outside the predetermined area
range, and wherein the computer is configured to indicate when the
contact point is outside the predetermined range.
12. The system of claim 10 wherein the computer is configured to
calculate alignment from the measurement data.
13. The system of claim 12 wherein the display is configured to
display movement of the contact point on the portion of the surface
on the display as a result of the prosthetic joint movement,
prosthetic component movement, tissue tensioning, bone cutting,
shimming the prosthetic component, or changes in loading on the
surface of the prosthetic component.
14. The system of claim 10 wherein the prosthetic component is
configured to be rotated, wherein the computer is configured to
calculate rotation of the prosthetic component from a reference
position from the measurement data, and wherein the display is
configured to indicate degrees of rotation from the reference
position of the prosthetic component.
15. The system of claim 10 wherein the display is configured to
indicate a range of the movement of the prosthetic joint or the
prosthetic component and wherein the graphical user interface
includes a graphical depiction of at least a portion of the
prosthetic joint, wherein the computer is configured to track
movement of the prosthetic joint, and wherein the graphical
depiction of the at least a portion of the prosthetic joint is
configured to move on the display corresponding to actual movement
of the prosthetic joint.
16. The system of claim 10 wherein the display can indicate a
predetermined area range on the portion of the surface on the
display and wherein the display is configured to indicate if the
contact point is within or outside the predetermined area range at
a glance.
17. An orthopedic measurement system for kinetic assessment
comprising: a device having a surface configured to couple to a
joint of a musculoskeletal system comprising at least one sensor
configured to measure one or more parameters wherein the device
includes a tracking system; a computer configured to receive
measurement data from at least one sensor and the tracking system;
a display coupled to the computer, wherein the display includes a
graphical user interface, wherein a memory and one or more
processors are configured to execute one or more programs stored in
the memory, wherein the computer is configured to receive
measurement data from the at least one sensor of the device,
wherein the graphical user interface includes a graphical depiction
of a portion of a surface of the device that is configured to
couple to the joint, wherein a contact point is displayed on the
graphical depiction of the portion of the surface of the device,
wherein the computer is configured to use the measurement data to
calculate a contact point location on the graphical depiction of
the portion of the surface of the device, wherein the contact point
is configured to move in real-time corresponding to movement of the
joint, and wherein the graphical user interface includes a
graphical depiction of at least a portion of the joint, wherein the
computer is configured to track movement of the joint, and wherein
the graphical depiction of the at least a portion of the joint is
configured to move on the display corresponding to actual movement
of the joint.
18. The system of claim 17 wherein the device is a prosthetic
component of the joint.
19. The system of claim 18 wherein the prosthetic component is
configured to display movement of the contact point on the portion
of the surface on the display as a result of prosthetic joint
movement, prosthetic component movement, tissue tensioning, bone
cutting, prosthetic component rotation, shimming the prosthetic
component, or changes in loading on the surface of the device.
Description
FIELD OF THE INVENTION
The invention relates in general to medical and surgical procedures
and more particularly to aligning medical devices to precise
locations on or within a patient's body.
BACKGROUND OF THE INVENTION
Orthopedic alignment currently involves cycles of trial and error.
For example, leg alignment requires a technique that approximates
alignment in which the surgeon makes one of the distal femoral cut
and the proximal tibial cut based on experience, mechanical jigs,
and visual alignment. Typically, the proximal tibial cut is made so
as to remove the least amount of the proximal tibia, while ensuring
sufficient removal of diseased or otherwise undesirable bone. The
remaining femoral cuts are made to complete shaping of the femur to
receive a femoral prosthesis. After the femoral and tibial cuts are
complete, the femoral prosthesis and the tibial prosthesis, or
trial versions thereof, are temporarily implanted and the surgeon
reviews leg alignment. Typically, no adjustments are made if the
leg is within a few degrees varus or valgus of the mechanical axis.
An insert has a bearing surface that allows articulation of the
leg. A set of shims can be coupled to the insert. The shims are
used to change the thickness of the insert. A shim and insert
combination is chosen that produces the best subjective movement
characteristics of the joint through a full the range of motion.
The surgeon may modify the bone or perform soft tissue tensioning
to affect load, rotation or alignment characteristics. In general,
the implant procedure is performed using the subjective skills of
the surgeon to achieve appropriate leg alignment, rotation,
balance, and soft tissue tension-loading.
Even with mechanical jigs, trialing, and advanced prosthetic
components, outcomes including functional efficacy, patient
comfort, and longevity of the prosthesis may not always be highly
predictable, especially if procedures are performed by physicians
and surgeons with different levels of skill, experience, and
frequency of repeating an individual procedure. This may be
confirmed by various reports in the literature that suggest a
positive relationship between outcomes and the numbers of
procedures performed annually by individual surgeons.
Accurately determining and aligning an implant orientation is a
difficult process requiring expensive equipment. A simple,
efficient method is needed to reduce medical costs and time of the
surgical procedure, while maintaining accuracy.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of present invention will become more fully understood
from the detailed description and the accompanying drawings,
wherein:
FIG. 1A illustrates a simplified view of directions of motion
referred to herein;
FIG. 1B illustrates the comparison between vargus and valgus;
FIG. 1C illustrates a simplified view of a physician using at least
one embodiment of a motion and orientation sensing device (e.g., a
surgical tracking system) with a computer display (e.g., a surgical
tracking display system);
FIG. 2 illustrates a top view of a tibia and associated reference
axis;
FIG. 3 illustrates a side view of a tibia and associated reference
axis;
FIG. 4 illustrates a user obtaining a reference axis by moving a
sensor;
FIG. 5 illustrates a user obtaining an alignment by moving an
orthopedic system;
FIG. 6 illustrates a user obtaining alignment data using a
sensor;
FIGS. 7 and 8 illustrates a user moving an orthopedic system in
extension to obtain alignment data;
FIGS. 9 and 10 illustrates a user moving an orthopedic system in
flexion to obtain alignment data;
FIGS. 11 and 12 illustrates a user moving an orthopedic system in
flexion to obtain alignment data
FIGS. 13 and 14 illustrates a user moving an orthopedic system in
elevated extension to obtain alignment data;
FIG. 15 illustrates a user moving an orthopedic system in elevated
extension to obtain alignment data;
FIG. 16 illustrates an electronic display showing a schematic of a
sensor, with orthopedic parametric values and a display of the
orthopedic system;
FIGS. 17-36 illustrates portions of a software display of a user
assist computer program;
FIGS. 37-38 illustrates various device zeroing configurations;
FIG. 39 illustrates a device orientation to obtain reference axis
data;
FIG. 40 illustrates an adapter and device that can be coupled to a
cutting jig;
FIG. 41 illustrates the adapter and device coupled together;
FIG. 42 illustrates a cutting jig and the associated adapter and
sensor device;
FIG. 43 illustrates an incorporated cutting jig system including
the adapter and sensor device;
FIG. 44 illustrates the incorporated cutting jig system in a
cutting position in an extended orthopedic system;
FIG. 45 illustrates the incorporated cutting jig system in a
cutting position in a flexion orientation, changing vargus and
valgus of the cutting jig;
FIG. 46 illustrates the incorporated cutting jig system in a
cutting position in an extension system, changing the A-P angle of
the cutting jig;
FIG. 47 illustrates two cutting jig systems being aligned;
FIG. 48 illustrates a femur rotation guide; --
FIG. 49 illustrates using the femur rotation guide to adjust
condial orientation;
FIG. 50 illustrates a tibia reference tool used for alignment;
FIG. 51 illustrates another view of the tibia reference tool used
for alignment;
FIG. 52 illustrates a method of measuring joint alignment between
first and second bones;
FIG. 53 illustrates another method of measuring joint alignment
between first and second bones;
FIG. 54 illustrates another method of measuring joint alignment
between first and second bones;
FIG. 55 illustrates a method of measuring alignment of a tibia to a
mechanical axis of a leg;
FIG. 56 illustrates another method of measuring alignment of a
tibia to a mechanical axis of a leg;
FIG. 57 illustrates another method of measuring alignment of a
tibia to a mechanical axis of a leg;
FIG. 58 illustrates method of measuring alignment of a femur;
FIG. 59 illustrates another method of measuring alignment of a
femur;
FIG. 60 illustrates another method of measuring alignment of a
femur;
FIG. 61 illustrates a method of measuring slope or tilt of a
prepared bone surface of a bone;
FIG. 62 illustrates another method of measuring slope or tilt of a
prepared bone surface of a bone;
FIG. 63 illustrates a method of measuring slope or tilt of a tibial
prosthetic component coupled to a tibia;
FIG. 64 illustrates another method of measuring slope or tilt of a
tibial prosthetic component coupled to a tibia;
FIG. 65 illustrates another method of measuring slope or tilt of a
tibial prosthetic component coupled to a tibia;
FIG. 66 illustrates a method of referencing a three-axis
accelerometer to measure location, tilt, and rotation of the
muscular-skeletal system;
FIG. 67 illustrates another method of referencing a three-axis
accelerometer to measure location, tilt, and rotation of the
muscular-skeletal system;
FIG. 68 illustrates a method of kinetic assessment, joint
modification, and installation of a final prosthetic joint;
FIG. 69 illustrates a method of kinetic assessment, joint
modification, and installation of a final prosthetic joint;
FIG. 70 illustrates another method of kinetic assessment, joint
modification, and installation of a final prosthetic joint;
FIG. 71 illustrates another method of kinetic assessment, joint
modification, and installation of a final prosthetic joint;
FIG. 72 illustrates another method of kinetic assessment, joint
modification, and installation of a final prosthetic joint;
FIG. 73 illustrates a method of kinetic knee assessment for
installing a prosthetic knee joint;
FIG. 74 illustrates a method of adjusting a contact point of a
joint system where a prosthetic component is coupled to a bone;
FIG. 75 illustrates another method of adjusting a contact point of
a joint system where a prosthetic component is coupled to a
bone;
FIG. 76 illustrates another method of adjusting a contact point of
a joint system where a prosthetic component is coupled to a
bone;
FIG. 77 illustrates a method of adjusting a tibial prosthetic
component in a knee joint;
FIG. 78 illustrates another method of adjusting a tibial prosthetic
component in a knee joint;
FIG. 79 illustrates another method of adjusting a tibial prosthetic
component in a knee joint;
FIG. 80 illustrates another method of adjusting a tibial prosthetic
component in a knee joint;
FIG. 81 illustrates method of measuring tilt of a prepared bone
surface of a muscular-skeletal joint;
FIG. 82 illustrates another method of measuring tilt of a prepared
bone surface of a muscular-skeletal joint;
FIG. 83 illustrates another method of measuring tilt of a prepared
bone surface of a muscular-skeletal joint;
FIG. 84 illustrates a method of measuring medial-lateral tilt of a
prepared bone surface of a knee joint;
FIG. 85 illustrates another method of measuring medial-lateral tilt
of a prepared bone surface of a knee joint;
FIG. 86 illustrates another method of measuring tilt of a prepared
bone surface of a muscular-skeletal joint;
FIG. 87 illustrates another method of measuring tilt of a prepared
bone surface of a muscular-skeletal joint;
FIG. 88 illustrates another method of measuring tilt of a prepared
bone surface of a muscular-skeletal joint;
FIG. 89 illustrates a method of measuring medial-lateral tilt of a
distal end of a femur of a knee joint;
FIG. 90 illustrates a method of generating a reference
position;
FIG. 91 illustrates axes associated with a sensor and
rotations;
FIG. 92 illustrates a plot of the acceleration in the x direction
versus angle of inclination of a sensor;
FIG. 93 illustrates a descriptive figure of a method in accordance
with an embodiment;
FIGS. 94A and 94B illustrate horizontal orientations used in
calibration in accordance with an embodiment; and
FIG. 95 illustrates a vertical orientation used in calibration in
accordance with an embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
The following description of embodiment(s) is merely illustrative
in nature and is in no way intended to limit the invention, its
application, or uses.
For simplicity and clarity of the illustration(s), elements in the
figures are not necessarily to scale, are only schematic and are
non-limiting, and the same reference numbers in different figures
denote the same elements, unless stated otherwise. Additionally,
descriptions and details of well-known steps and elements are
omitted for simplicity of the description. Notice that once an item
is defined in one figure, it may not be discussed or further
defined in the following figures.
It will be appreciated by those skilled in the art that the words
"during", "while", and "when" as used herein relating to circuit
operation are not exact terms that mean an action takes place
instantly upon an initiating action but that there may be some
small but reasonable delay, such as a propagation delay, between
the reaction that is initiated by the initial action. Additionally,
the term "while" means that a certain action occurs at least within
some portion of duration of the initiating action. The use of the
word "approximately" or "substantially" means that a value of an
element has a parameter that is expected to be close to a stated
value or position. However, as is well known in the art there are
always minor variances that prevent the values or positions from
being exactly as stated.
The terms "first", "second", "third" and the like in the Claims
or/and in the Detailed Description are used for distinguishing
between similar elements and not necessarily for describing a
sequence, either temporally, spatially, in ranking or in any other
manner. It is to be understood that the terms so used are
interchangeable under appropriate circumstances and that the
embodiments described herein are capable of operation in other
sequences than described or illustrated herein.
Processes, techniques, apparatus, and materials as known by one of
ordinary skill in the art may not be discussed in detail but are
intended to be part of the enabling description where appropriate.
For example specific methods of attaching a surgical device onto
the surgical device holder, however one of ordinary skill would be
able, without undo experimentation, to establish the steps using
the enabling disclosure herein.
The terms precision and resolution can be used herein to
specifically have the standard definitions. Precision will connate
the variation from exactness. Resolution will have the customary
definition of the smallest measurable interval. The orientation of
the x, y, and z-axes of rectangular Cartesian coordinates is
assumed to be such that the x and y axes define a plane at a given
location, and the z-axis is normal to the x-y plane. The axes of
rotations about the Cartesian axes of the device are defined as
yaw, pitch and roll. With the orientation of the Cartesian
coordinates defined in this paragraph, the yaw axis of rotation is
the z-axis through body of the device. Pitch changes the
orientation of a longitudinal axis of the device. Roll is rotation
about the longitudinal axis of the device.
The orientation of the x, y, z axes of rectangular Cartesian
coordinates is selected to facilitate graphical display on computer
screens having the orientation that the user will be able to relate
to most easily. Therefore the image of the device moves upward on
the computer display whenever the device itself moves upward for
example away from the surface of the earth. The same applies to
movements to the left or right.
The terms `motion sensing` and `tilt sensing` and `orientation` is
also intended to have specific meaning. `Motion sensing` indicates
the detection of movement of a body that exceeds a specified
threshold in one or more coordinate axes, for example the specific
threshold in one or more Cartesian axes in terms of both static and
dynamic acceleration. `Heading` is defined as the orientation of
longitudinal axis of the motion of the motion and orientation
sensing module or device and movement in a direction. `Tilt` is
defined as the orientation of a body with respect to a zenith. The
term slope is used interchangeable with the term "tilt." Tilt
sensing' indicates the measurement of acceleration attributable to
gravity in one or more axes. `Orientation` includes yaw as well as
`tilt.` Note that although accelerometers are provided as enabling
examples n the description of embodiments, any tracking device
(e.g., a GPS chip, acoustical ranging, magnetometer, gyroscope,
inclinometers, MEMs) can be used within the scope of the
embodiments described.
Note that the term flexion value is used herein. For purposes of
this disclosure a flexion value of approximately 180 degrees is
full extension, and any value other than 180 degrees is a joint in
flexion where the bones on either side of the joint intersect form
an angle. Note also tolerance values are those known by one of
ordinary skill in the arts, for example subjective tolerance on
angle measurements can be 1 to 3 degrees.
At least one embodiment is directed to a kinetic orthopedic (e.g.,
knee) balancer system to aid a surgeon in determining real time
alignment and loading of orthopedic implants. Although the system
is generic to any orthopedic surgery (e.g., spinal, shoulder, knee,
hip) the following examples deal with knee surgery as a
non-limiting example of an embodiment of the invention.
The non-limiting embodiment described herein is related to
quantitative measurement based orthopedic surgery and referred to
herein as the kinetic system. The kinetic system includes a sensor
system that provides quantitative data and feedback that is
displayed visually and/or audibly and/or haptically to a surgeon.
The kinetic system provides the surgeon real time dynamic data
regarding loads in each compartment of the knee, tibio-femoral
implant contact and congruency through a full range of motion, and
information regarding angular bony cuts and leg alignment.
In general, kinetics is the study of the effect of forces upon the
motion of a body or system of bodies. Disclosed herein is a system
for kinetic assessment of the muscular-skeletal system. The kinetic
system can be for the installation of prosthetic components or for
monitoring and assessment of permanently installed components to
the muscular-skeletal system. For example, installation of a
prosthetic component can require one or more bone surface to be
prepared to receive a device or component. The bone surfaces are
cut to place the prosthetic component in a relational position to a
mechanical axis of a joint. The kinetic system is designed to take
quantitative measurements of at least the load, position of load,
and alignment with the forces being applied to the joint similar to
that of a final joint installation. The sensored measurement
components are designed to allow ligaments, tissue, and bone to be
in place while the quantitative measurement data is taken. This is
significant because the bone cuts take into account the kinetic
forces where a kinematic assessment and subsequent bone cuts could
be substantial changed from an alignment, load, and position of
load once the joint is reassembled.
Measurements data supplement the subjective feedback of the surgeon
to ensure optimal installation. The quantitative measurements can
also be used to determine adjustments to bone, prosthetic
components, or tissue prior to final installation or to fine tune
the installation. Permanent sensors in the final prosthetic
components can provide periodic data related to the status of the
implant in use. Data collected intra-operatively and long term can
be used to determine parameter ranges for surgical installation and
to improve future prosthetic components. The physical parameter or
parameters of interest can include, but are not limited to,
measurement of load, force, pressure, position, displacement,
density, viscosity, pH, spurious accelerations, and localized
temperature. Often, several measured parameters or different
measurements are used to make a quantitative assessment. Parameters
can be evaluated relative to orientation, alignment, direction,
displacement, or position as well as movement, rotation, or
acceleration along an axis or combination of axes by wireless
sensing modules or devices positioned on or within a body,
instrument, appliance, vehicle, equipment, or other physical
system.
FIG. 1A illustrates the basic directions and motions discussed
herein with reference to a surgeon/user 180 and a patient 111. For
example, the vertical axis 100A is perpendicular to the table 117
upon which the patient 111 lies. The vertical axis 100A points to
the anterior direction. The axis 100B is parallel but opposite to
the vertical axis 100A and points to the posterior direction. In
the patient configuration shown corresponding to the left leg of
patient 111 the axis 101 points to the lateral side of the knee
while the axis 102 points to the medial side of the left knee.
Thus, if a device is situated at the vertical axis 100A in the left
knee and pivoted about the 103 and 104 axis in the 101 axis
direction the device is being rotated in the lateral direction.
Conversely, if the device is pivoted about the 103 and 104 axis in
the 102 axis direction the device is being rotated in the medial
direction. The knee joint move through an arc corresponding to axis
101A and axis 102A when rotated laterally and medially. In a first
example of a pivot point the heel of the foot can be placed at a
fixed position on the operating table along axis 104 to 103. The
knee joint pivots off of heel of the leg but can be rotated along
the axis 101A and the axis 102A. In a second example of a pivot
point, the heel is lifted off of the operating table and the leg is
pivoted off of the hip joint. The pivot point is the femoral head
of the femur. Typically, the hip joint is at a fixed position on
the operating table. The knee joint pivots off of the femoral head
of the femur but can be rotated along the axis 101A and the axis
102A. The angle of the device in the knee joint can be changed by
moving the pivot point of the heel in the direction 104 or the
direction 103. For example, moving the heel in direction of the
axis 104 will move the joint towards the posterior position 100B
that correspondingly changes the angle of flexion.
FIG. 1B illustrates a muscular skeletal system showing a medial
lateral line 191A. The mechanical axis of a non-deformed leg is
illustrated by the vertical dashed line 191B as illustrated in view
191. View 193 illustrates a leg having a varus deformity. A varus
angle 193A illustrates a varus offset with respect to the
mechanical axis of a non-deformed leg. View 195 illustrates a
valgus deformity. A valgus angle 195A illustrates a valgus offset
with respect to the mechanical axis of a non-deformed leg.
FIG. 1C illustrates a kinetic system that includes data displayed
in a GUI 100 that can provide feedback to a surgeon 180
before/during/and after surgery on a patient 190. The GUI 100 is
displayed on a screen 105, which can be interacted with verbally
(e.g., via microphone), or haptically via a hand held control 130,
and/or a mouse 110, and/or a keyboard 120. The GUI 100 can provide
quantitative measurement data from sensors (e.g., placed in
implants, sensor on probes or surgical instruments). A computer,
processor, digital signal process coupled to screen 105 can run
software programs that use the quantitative measurements from the
sensors to visualize the on-going procedure, review measurement
data, positions of the muscular-skeletal system, support
modifications, and generate workflows based on the quantitative
measurement data to support an optimal fit of the prosthetic
components. Some non-limiting examples of information include:
device type 140, device ID 142, company 144, CP rotation 146,
Tibial rotation 148, HKA (Hip Knee Angle) 150, Tibia angle 152, A-P
angle 154, flexion 156, implant 157 (e.g., tibial insert),
localized load indicators 158, medial and lateral load scales 159
with ranges 160, joint orientation display 162, a signal indicator
button 163, a zeroing initiation button 164, a track button 165, a
clear button 171, an align button 166, a power indicator 169, a
power on button 170, and several other buttons that can be used for
other features 167 and 168.
Initial setup for a knee replacement surgery can involve evaluating
a patient's x-rays of the knee joint. FIG. 2 illustrates an AP
(anterior-posterior) view of the tibia/knee region. From the view
in FIG. 2 the surgeon can define the varus/valgus plane (e.g. plane
defined by plane intersecting line 200 and 210) and the depth of
proposed bone cuts.
In addition to AP views the surgeon uses lateral views to determine
posterior slope or determine cut angles. FIG. 3 illustrates a
lateral view of the tibia knee area. As mentioned the lateral view
allows the surgeon to determine the anterior-posterior slope or how
much of an angle to cut from anterior to posterior of the proximal
tibia trying to recreate the patients natural slope. A bone jig can
be attached to the proximal end of the tibia to prepare a proximal
end of the tibia 220 for receiving a prosthetic component. The bone
jig can be adjusted to provide a medial-lateral bone slope and an
anterior-posterior bone slope. As disclosed herein below,
quantitative measurements are used to determine kinetic bone cuts
under forces that are similar to what the final installed
components will see. The kinetic system will provide measurements
of the misalignment of the tibia to the mechanical axis of the leg
that will be compensated for in the bone jig adjustment for the
medial-lateral portion of the tibial bone cut. Similarly, the
kinetic system will measure the misalignment of a femur to the
mechanical axis of the leg, which can also be compensated for by
one or more bone cuts.
In the non-limiting embodiment discussed herein we can use
medial-lateral views to determine an AP (anterior-posterior) slope.
For example, two lines (330 and 340) intersecting the proximal
tibial line 300, will be defined below, but for now make angles 310
and 320 respectively with the proximal tibial line 300, where the
difference in the angles (i.e., 320-310) can used in a tibial bone
cut calculation. The first line, 330 bisects the tibial canal from
the ankle to the insertion of the ACL (e.g., on the anterior 1/3 of
the tibial plateau) to the native slope of the tibial plateau. The
second line 340 runs parallel to the tibial crest 345 that
intersects the tibial plateau native line as well. In the example
embodiment, the anterior-posterior slope of the bone cutting jig is
adjusted by quantitative measurement under forces similar to that
of the final prosthetic component installation as will be disclosed
herein below. The amount of anterior-posterior slope cut into tibia
220 is often dictated by the knee joint and the knee joint
components being used. For example, if the posterior cruciate
ligament is removed an insert with a post is often used to provide
support to the joint. An anterior-posterior slope is cut into tibia
220 to support range of motion of the joint in flexion in
conjunction with the post.
The measurement device or sensored device comprises at least a
pressure sensor system to measure load magnitude and position of
load magnitude. The measurement device further includes at least
one three-axis accelerometer. In one embodiment, the three-axis
accelerometer is referenced to gravity to measure position,
rotation, and tilt or slope. The sensing system can be integrated
into a prosthetic component. In the example, the sensored device is
an intra-operative trial insert. The trial insert includes at least
one articular surface that supports movement of the joint. As
shown, herein the insert has two aritcular surfaces. The trial
insert is substantially similar in size to a final insert. The
trial insert allows all the ligaments, tendons, tissue, and bone
structures that apply forces to the joint to be in place during the
kinetic assessment to provide quantitative data on load, position
of load, and alignment. The trial insert can be wired or wireless
for transmitting data to a remote system. The remote system can
include a display, software, and a microprocessor, microcontroller,
or digital signal process. The remote system is typically outside
the surgical field but can be viewed by the surgical team. The
sensing system can also be in a trial tibial prosthetic component
or a femoral prosthetic component. Similarly, the measurement
device can be integrated into a permanent prosthetic component. An
example for a knee application integrating the measurement device
into a tibial prosthetic component. Alternatively it could be
integrated into the permanent femoral prosthetic component or
insert.
In FIG. 4 a trial insert or sensored insert 425 is referenced to
establish reference planes for position, rotation, and tilt or
slope. The insert 425 is referenced to a first plane. In the
example, insert 425 is referenced to the operating table. The
insert 425 is then referenced to a second plane. The second plane
is perpendicular to the first plane. The accelerometer in the
sensored insert 425 measures the plane of the operating table in a
first direction and then the sensored insert is rotated 180 degrees
and a second measurement is taken. The two accelerometer
measurements are averaged to remove any slope the operating table
may have. The accelerometer is zeroed to the plane of the operating
table. The accelerometer is then zeroed to the plane that is
perpendicular to the table. A block can be held at a 90 degree
angle to the plane of the table and insert 425 held against the
block and zeroed to the plane. Alternatively, a structure can be
attached or coupled to the table that has a reference plane that is
perpendicular to the surface of the table. Insert 425 can be held
to the structure and zeroed to plane perpendicular to the operating
table surface. A more detailed explanation of the referencing
process is disclosed in FIGS. 37 and 38.
A reference position of the joint is established to support further
measurement and positioning of the joint. In the example, the leg
is placed in a position of approximately extension. The position
does not have to be in extension in the strictest definition of the
term but a position that the surgeon can repeatably place the leg
in. In one embodiment, a tibia reference is captured. The tibia
reference represents the position of the tibia when the leg is in
full extension. For example, the leg can be placed with the heel
touching the operating table at a fixed location. Alternatively,
the distal portion of the leg can be placed in a leg holder for
repeatable placement and positioning. Upon placing the leg in
approximately extension insert 425 will be referenced to a bone
landmark or other repeatable reference related to the leg in
extension. In the example, the position or angle of a tibial crest
427 is measured by the surgeon 400 when the leg is in extension.
Posterior edges of insert 425 are held against a tibial crest 427.
The tibial crest is below the tibial tubercle and provides a large
surface area to contact. Insert 425 is held approximately
perpendicular to the plane of the surface of the operating table on
the tibial ridge. The surgeon will move 420 the posterior of insert
425 against the tibial crest until it is stabilized against the
crest. A three axis accelerometer 410 in insert 425 measures the an
angle of tibial crest 427 in extension. The measurement data is
transmitted to a remote system having a GUI. The GUI displays the
angle of insert 425 relative to vertical and the angle of tibial
crest 427. With the leg in extension the angle of insert 425 is
held within -2 and 2 degrees of vertical to ensure an accurate
measurement. In one embodiment the system captures the angle of the
tibial crest when the angle of insert 425 is within -2 degrees and
+2 degrees. Typically, the angle of the tibial crest is
approximately 3 degrees for a large portion of the population. The
GUI will show the angle of the tibial crest on an indicator from
the measurement data transmitted from accelerometer 410 to the
remote system. Insert 425 is then referenced to this angle whereby
the GUI indicates that the leg is in extension when the tibia is
placed in the same position. In one embodiment, a flexion indicator
of the GUI is used to display the angle of insert 425 measured to
vertical. A tray rotation indicator of the GUI is used to display
the angle of tibial crest 427. Thus, a bone landmark has been
referenced by the system. A position of extension is indicated on
the GUI when the bone landmark is placed in the reference position.
In the example, GUI indicators are used more than once to indicate
certain steps of a procedure to reduce the number of indicators and
reduce clutter on the display. The user of the system can then
rapidly synthesize the information being displayed to reduce
surgical time. In one embodiment, the AP (anterior-posterior) slope
or tilt indicator will be displayed on the display of the remote
system after reference the tibia for a position of extension.
In FIG. 5 a surgeon 500 can place a sensored insert 510 on a
proximal portion 520 of tibial bone cutting jig 530. In one
embodiment, a shim having a tab is coupled to insert 510. The tab
of the shim is coupled to bone cutting jig 530. In the example, the
tab is inserted into a cutting slot of bone cutting jig 530.
Sensored insert 510 can be used to define through quantitative
measurements the medial-lateral (ML) and anterior-posterior (AP)
bone cuts of tibial bone cutting jig 530. For example, the
accelerometer in sensored insert 510 can be used to measure tilt or
slope to obtain a measurement of the jig angle in the AP plane
prior to the cut. Furthermore, sensored insert 510 can be similarly
placed on a distal femoral jig to define if the sagittal plane is
parallel to the tibial cut or to produce a cut offset to the tibial
cut. The GUI 100 flexion angle 156 will depict the angle of the
proposed tibial cut in the AP plane. The process of using sensored
insert with bone cutting jigs will be disclosed in more detail
hereinbelow.
In FIG. 6 the surgeon 400 takes a sensored insert 425 and places it
into a knee tibial prosthetic component 600. Tibial prosthetic
component 600 can be a trial or permanent component. Tibial
prosthetic component 600 can be fixed to the tibia that supports
movement. For example, tibial prosthetic component 600 can be held
to the tibia via a single pin that allows rotation. Typically, how
tibial prosthetic component 600 is aligned to the tibia is a choice
of the surgeon. In one embodiment, tibial prosthetic component 600
is positioned or aligned to a bone reference whereby tibial
prosthetic component 600 can be placed consistently from patient to
patient. The initial placement or alignment of tibial prosthetic
component 600 is a reference position. In general, leg 610 is in
flexion when inserting sensored insert 425 into the knee joint. In
one embodiment, insert 425 is inserted into a tibial tray of tibial
prosthetic component 600. Insert 425 can include a shim to increase
or decrease insert height or thickness. A change in insert 425
thickness is required if the joint is too loose or too tight when
moving through the range of motion. The tibial tray retains insert
425 in a fixed position relative to tibial prosthetic component
600. Insert 425 couples to a femoral prosthetic component and
tibial prosthetic component 600. Insert 425 has at least one
articular surface. In the example, has two articular surfaces that
allow the leg to move through a range of motion. The leg can then
be placed in extension 620 as measured by the accelerometer and
indicated on GUI 100. The AP box 154A on the GUI is clicked to
measure the AP slope or tilt of the proximal tibial cut as
referenced to the tibial crest or any chosen referenced plane
(e.g., cutting rod etc. . . . ). In general, the accelerometer in
insert 425 is coupled to the tibia and measures the
anterior-posterior slope of the bone cut on the proximal end of the
tibia relative to the referenced tibial crest. Thus, the A-P slope
measurement can be made independent of the leg position.
FIGS. 7 and 8 illustrate the surgeon 400 or surgical team
interfacing with the GUI to set A-P slope. In particular, box 154A
and box 156A of the GUI are shown. Box 154A and Box 156A
respectfully correspond to A-P (anterior-posterior) slope and
flexion position of the leg. In FIG. 7 the leg is moved into a
position 701 of extension. As shown, the measurement can indicate
that the leg is hyper-extended with a negative reading (e.g. -3.5
degrees) relative to the floor. In the example, the proximal end of
the tibia has been cut with an anterior-posterior slope or tilt.
The tibial tray of the tibial prosthetic component takes on this
slope when mounted to the tibia. Thus, the insert in a knee 610
couples to the tibial tray of the tibial prosthetic component and
measures the anterior-posterior slope thereof, which appears to
show a hyper-extended knee. Note that in at least one embodiment
the AP box shows the slope, and the flexion angle is relative to
the floor or gravity.
FIG. 8 illustrates measuring and setting the A-P slope on the GUI.
The leg remains in extension or the same position when the Tibial
reference was taken, until Box 154A is selected or clicked on. The
measurement of the A-P slope is then taken. The flexion measurement
of Box 156A is transferred to Box 154A. In the example, a positive
slope for A-P corresponds to the anterior side proximal end of the
tibia being higher than the posterior side. Thus, the A-P slope as
shown is measured at 3.5 degrees in the example. The A-P slope
measurement can be used to verify that the cut was correct. If the
A-P slope is incorrect as shown by Box 154A correction or
modification can be undertaken to change the slope. The A-P slope
is stored in memory and can be used in further computations and
measurements. Changes to the slope can be re-referenced after
adjustments are made. The resultant position is the optimized
position of the accelerometer in the sensored insert to define the
proximal tibial A-P angles that were cut. As will be disclosed
herein below the sensored insert can be coupled to a tibial bone
cutting jig pre-cut to define a tibial cut of 3.5 degrees A-P
slope. In general, an A-P slope is useful to define flexion gap
balance and equalize loading when the leg is moved from extension
into flexion.
FIGS. 9 and 10 illustrate the surgeon measuring the offset of the
tibia to the mechanical axis of the leg. Prior to measuring the
offset the CP (contact point) rotation is set. The CP rotation
corresponds to a reference position of the tibial femoral
prosthetic component to the prosthetic component. The Tibial Try
Rotation box corresponds to a reference position of the tibial
tray. For example, many surgeons align the center of the tibial
tray of the tibial prosthetic component to the medial third of the
tibial tubercle or other landmark. As mentioned previously, the
tibial tray can be pinned to the tibia in a manner that allows
rotation of the tibial prosthetic component from the reference
position. A Tibial Rotation box on the GUI is selected or clicked
once the reference position of the tibial tray is established. Any
change in the position of the tibial tray is indicated in the
Tibial Rotation box of the GUI. In one embodiment, the reference
position is listed as zero degrees in the Tibial Tray Rotation box.
Alternatively, CP Rotation can indicate an amount of tray or insert
rotation relative to the femoral condylar contact on the tibial
tray. Rotating the tibial prosthetic component will yield a
positive or negative number in the Tibial tray Rotation box
depending on the direction of rotation. In one example, rotating
the tibial prosthetic component can be used to affect the position
of load and the load magnitude over the range of motion. In one
embodiment, the GUI can indicate if the load magnitude is within a
predetermined load range. Similarly, the GUI can indicate if the
position of load is within a predetermined position range. The
value of CP Rotation can be used in measurement and calculations of
other parameters such as the congruency of the tibial and femoral
implants through a full range of motion.
In FIG. 9, the knee joint is placed in flexion. In the example, the
sensored insert is positioned to be at approximately a 45 degree
angle to the plane of the surface of the operating table. The heel
is positioned in a fixed position to achieve the sensored insert
angle optimized position for reading outputs. The GUI directs the
surgeon to this flexion angle. In one embodiment, the heel is
placed on the surface of the operating table. The position of the
heel on the operating table should fixed in place as it will be a
first pivot point for moving the knee joint. Surgeon 400 can hold
and stabilize the ankle and heel to minimize movement during the
measurement. In one embodiment an align button on the GUI is
pressed to initiate alignment measurements. Surgeon 400 now follows
a needle point graphic or tracking grid 930 on the GUI to begin
rocking the knee back and forth with the heel 910 placed firmly on
the operating table in a stable position, to allow pivoting 920 on
the heel to define a plane to reference to. As shown, the knee
joint is pivoted in the lateral direction and tracking grid 930
tracks the movement. In FIG. 10, the knee joint is pivoted in the
medial direction and tracking grid 930 tracks the movement. The
surgeon limits the movement within the range of tracking grid 930.
In general, a maximum of the arc made by the knee joint is being
identified by the system. The range of the arc is less or equal to
plus or minus 45 degrees from vertical. In one embodiment, the arc
is less than or equal to plus or minus 10 degrees from vertical.
The maximum has to be within the range of tracking grid 930.
Reducing the range of the arc improves measurement accuracy since
the same amount of measurements are taken for any given range. The
knee joint is rocked to the medial side and the lateral side more
than one time. In one embodiment, the knee joint can be rocked back
and forth ten times or less to identify arc maximum. Increasing the
analog to digital converter accuracy can be used to reduce the
number of rocking motions. In one embodiment, the analog to digital
converter accuracy used in the measure of the arc maximum utilizes
DAC's (digital to analog converters) having 15-bit or greater
accuracy. The number of rocking motions can be reduced to four or
less rocking motions using a DAC's of 15-bit or greater accuracy
which reduces the time and effort required by surgeon to measure
points in the arc. In general, the accelerometer is referenced to
three axis. A first axis corresponds to the A-P
(anterior-posterior) line of the knee joint. A second axis
correspond to the M-L (medial-lateral) line of the knee joint. The
third axis is perpendicular to the plane of the first and second
axis. In one embodiment, the sensored insert is measuring and
finding the maximum gravity in the X-direction or along the A-P
line. At maximum gravity in the X-direction raw tibial tray
rotation of the tibial prosthetic component should be zero in the
Y-direction or along the M-L line. In the system,
Y-direction/X-direction is rotation and tilt is
Y-direction/Z-direction. If the measurement is not zero then the
tibia has tilt which is measured. The amount of tilt can be related
to a varus or valgus angle relative to the mechanical axis. Thus,
as the surgeon 400 is pivoting 920 on the heel, the system searches
for the Max G for the sensored insert. The location of the maximum
is used to determine an offset from the mechanical axis of the leg.
The offset corresponds to a varus-valgus angle for the tibia.
As mentioned previously, the knee joint can be positioned where the
sensored insert is at a 45 degree angle relative to the surface of
the operating table to improve measurement accuracy. The
aforementioned position of the insert is a point where the axis of
the A-P line and the axis normal to the plane are approximately
equal in terms of the effect of gravity. In one embodiment, the
flexion box in the GUI can indicate when the sensored insert is in
an optimal position prior to measuring the leg alignment. For
example, the number in the flexion box can change color to indicate
that the leg is positioned for measurement.
FIG. 11 illustrates a measurement of a tibia angle relative to the
mechanical axis appearing on the GUI. In the example, the knee
joint is pivoting 920 off of the heel of leg 610. The heel and
ankle are held together to prevent movement of the ankle. The knee
joint is moved back and forth in a medial direction and a lateral
direction a predetermined distance as indicated in tracking grid
930 (e.g. needle point graphic on the GUI). The back and forth
movement of the joint is performed a predetermined number of times.
A calculation of the varus-valgus angle appears on the display and
is listed under tracking grid 930 as "Tibia" in the GUI. The
varus-valgus angle corresponds to the medial-lateral tilt of the
proximal end of the tibia. For example, the tibia is in alignment
to the mechanical axis if the max G position corresponds to the A-P
line. If the max G position is offset from the A-P line then an
offset exists relative to the M-L line that can be converted to a
varus-valgus angle. The A-P slope and angle of flexion is also
indicated in the GUI.
The pace of the rocking motion can be dictated by tracking grid
930. The surgeon will try to pace the movement of the knee joint
back and forth to lead the needle shown in the GUI. For example,
moving the knee joint to quickly will result in the needle not
being able to follow the leg movement. The correct pace allows the
needle to track movement of the knee joint. The knee joint movement
should not move the needle outside either extreme. The sensored
insert is taking quantitative measurements over the arc to
determine the position of Max G.
FIG. 12 illustrates a completed measurement of the tibia relative
to the mechanical axis of the leg. The knee joint has been rotated
back and forth the predetermined number of times. Data points have
been taken to determine the maximum along the A-P line of the
joint. The amount of tilt or slope on the tibial plateau can be
calculated from the position of the maximum. Tibia angle 152C is
indicated on the GUI. A final calculation of tibia angle 152C can
be indicated by changing the display color and placing a box around
the number. The GUI further indicates whether the tibia angle is
varus or valgus 152D relative to the mechanical axis.
FIG. 13 illustrates a measurement of the femur of the leg relative
to the mechanical axis of the leg. The workflow of the system
having now captured the tibia offset to the mechanical axis now
captures the bone tilt or slope of the distal end of the femur. In
general, the difference in the leg alignment when compared to the
mechanical axis is calculated by subtracting the medial-lateral
bone tilt of the distal end of the femur from the medial-lateral
bone tilt of the proximal end of the tibia. This difference is
listed on the GUI underlying Mech. Axis (e.g. mechanical axis)
based on the tibia and femur quantitative measurements.
In one embodiment, the leg is placed back in extension 620. The leg
is lifted in extension 620 such that the distal end of the femur is
loaded by the knee joint. The leg in extension 620 is lifted until
the sensored insert in the knee joint is at a 45 degree angle or an
optimized angle as depicted on the GUI to the surface of the
operating table.
The leg is lifted so the leg is pivoting 620 off of the femoral
head of the femur. The leg is lifted such that the sensored insert
in the knee joint is at a chosen angle, for example approximately
45 degrees. In the example, the numbers in the GUI under Mech. Axis
will change color and a box is placed around the numbers when the
sensored insert is about the chosen angle, for example in the 45
degree position. The surgeon 400 now takes the leg in the extended
position 620 and moves the knee joint back and forth in the medial
and lateral direction. This will allow the system to subtend the
plane of the distal femoral implant or distal femoral angle. As
mentioned previously, the leg is pivoting off of the femoral head
of the femur when rocking back and forth.
In FIGS. 13 and 14, the leg is pivoted 1300 on the femoral head of
the femur. The knee joint is rocked back and forth and is tracked
by the tracking grid on the GUI. The surgeon moves the leg at a
pace that the tracking grid keeps up with the movement. Thus, the
tracking grid limits or controls how fast the surgeon moves the
knee joint. The range of the movement is also limited by the
tracking grid shown in the GUI. The surgeon limits the movement
within the range of the tracking grid. In one embodiment, the
surgeon moves the knee joint back and forth to either extreme of
the tracking grid. The knee joint moves in an arc. The system will
measure and identify the Max G position of the sensored insert
pivoted 1300 off of the femoral head of the femur and calculate the
tilt or slope of the medial-lateral distal end of the femur. The
tilt of the distal end of the femur is incorporated with the
previously measured tilt of the measured proximal end of the tibia
to output an offset relative to the mechanical axis as depicted in
the GUI in 151A and 151B. In one embodiment, the number can be
changing as the leg is rotated back and forth. The varus-valgus
angle is a measure of the offset of the femur to the mechanical
axis and corresponds to the measured medial-lateral tilt of the
distal end of the femur. For example, the femur is in alignment to
the mechanical axis if the max G position corresponds to the A-P
line. If the max G position is offset from the A-P line then an
offset exists relative to the M-L line of the distal end of the
femur that can be converted to a varus-valgus angle for the femur.
Thus, the varus-valgus offsets of the tibia and femur relative to
the mechanical axis is measured.
FIG. 15 illustrates a surgeon 400 rocking the leg in extended
position, pivoting on the femoral head, and the Max-G is identified
by accelerometer measurements of the sensored insert such that the
mechanical axis offset 151C is boxed. The boxing of the Mech. Axis
value is an indication that the predetermined number of rotations
has been completed and the offset value of relative to the
mechanical axis has been calculated. In the example, the mechanical
axis offset is measured as 0.8 degrees. This indicates that the
distal end of the femur was measured having a varus angle of 0.3
degrees. The combination of the tibia and femur offsets yields a
value of 0.8 degrees from the mechanical axis. In general, the
measurement can be used to verify that the leg measures within a
predetermined range of the mechanical axis. For example, there have
been clinical studies that indicate that an offset greater than 3
degrees can have significant issues with joint reliability. The
surgeon can verify to a high degree of accuracy that the leg
alignment is well within this limit. Moreover, as data is taken
with different bone geometries it may become standard to cut at
specific offsets for optimal fit and where which can be
accomplished by using the system with a bone cutting jig as will be
disclosed herein below. The surgeon can now evaluate the Total Knee
Replacement (TKR) result as it relates to alignment of the legs,
alignment of the bony cuts, the soft tissue tension and
femoral-tibial implant congruity.
FIG. 16 illustrates a non-limiting example of a GUI that the
surgeon can view which provides quantitative data, visualization,
and feedback. In one embodiment, the system can include a video
recording of the procedure. It illustrates a video 1600 of the
surgeon manipulating the leg, a representation of a sensored insert
157, with associated angular readings (e.g., CP Rotation,
Mechanical Axis angle, Tibia angle, AP angle, Flexion angle, and
Tray rotation), and loadings.
FIGS. 17-34 illustrate a GUI software system in accordance to at
least one embodiment of the invention, which displays information
that a surgeon can use during surgery. FIG. 17 illustrates a start
screen when the software system is begun. The software system
checks to make sure all devices (e.g., sensors) linked to the
system are turned off. If there are devices on, a message is
displayed 1710 to notify the user to turn off the devices and will
also indicate 1700 which device(s) are transmitting data. The user
is provided a button 1720 that can be selected for the software
system to shut off devices for the user. When the devices are off
and not transmitting data, the system can initialize any new device
that transmits data, search for devices, and remind 1800 the user
to activate the sensors if not detected (FIG. 18).
FIG. 19 illustrates the GUI system 100 after software activation
and sensor detection. The GUI system 100 indicates a progress bar
1900 showing the initializing of sensors (e.g., load sensors) a
cancel button is provided 1910 to allow the user to stop the
process. The GUI 100 can contain multiple information, for example
device type 140, device ID 142, company 144, flexion 156, device,
module, or prosthetic component 157 (e.g., tibial insert), a signal
indicator button 163, a zeroing initiation button 164, a track
button 165, a clear button 171, an align button 166, a power
indicator 169, a power on button 170, and several other buttons
that can be used for other features 167 and 168.
After initialization, the user is prompted 2000 to select a
particular anatomical feature (e.g., left 2010 or right 2020 leg)
that the sensors are being used for (FIG. 20).
FIG. 21 illustrates the GUI 100 after initialization and feature
selection. The user is prompted to zero the sensors (e.g. zero
button 164 turns red). In operation, during this stage, the
prosthetic device is coupled to a reference surface. In one
embodiment, the sensored insert is placed flat upon an operating
room (OR) table and then a user selects the zero button 164 on the
GUI to reference to the OR table surface. Once pressed the software
zeros the offsets in the sensors. As mentioned previously, the
sensored insert utilizes at least a three-axis accelerometer that
is referenced to gravity to measure position, tilt, and rotation.
When the zero button 164 is selected the GUI 100 notifies 2200 the
user that the sensor is being zeroed, and optionally provides a
button 2210 to allow cancellation of the zeroing by the user (FIG.
22). The zero button 164 can be deactivated (e.g., the text changes
from red to black) when the notification 2200 is provided.
FIG. 23 illustrates the GUI 100 display when the zeroing process is
complete. On GUI 100 a Tibial rotation 2300 is also displayed. In
one embodiment, tibial rotation 2300 corresponds to an amount of
rotation of a tibial tray of a tibial prosthetic component from a
reference position. The sensored insert zero'd in the plane of the
table can have a zero value for the x and y values. At this point
the device (e.g., implant 157) has not been placed in the
anatomical feature (e.g., leg), and the loading 160 in the device
shows 0.00 load values. After zeroing the device the first time it
can be rotated on the table about 180 degrees and zeroed a second
time for the new position. The software system can average the
measurement values at the two positions, minimizing affect of the
slope of the table. The x-y values have been obtained for the
accelerometer in the sensored insert (in the plane of the OR
table). The device is then stood vertically and positioned against
a plane perpendicular to the surface of the OR table to zero to a
reference z-plane. In one embodiment, a reference block having a
z-plane surface is held against the surface of the OR table.
Alternatively, a z-plane surface is available on the OR table.
After obtaining the zero reference values in the x-y plane and the
z direction, the device/sensor can be translated into a sterile
field (e.g., for operation).
Once moved to a sterile field, the tibia reference is captured, or
the reference of the position of the tibia when the leg is in full
extension (e.g., heel resting on table or leg holder). In the
example, this is a reference position selected by the surgeon that
corresponds to the leg in extension. This is done by resting the
posterior edges 2310 of the implant 157 along the tibial crest (see
FIG. 4) or any other bony prominence to define a plane. Tibial
Rotation 2300 is used to measure the angle of the tibial crest
relative to the plane of the OR table. Thus, tibial rotation 2300
that is provided from the GUI is the tibia crest reference angle
and not the tray rotation in this measurement. The user can then
click on the Flexion 156, where a blinking box 156A appears,
waiting for the user to now to rotate the implant 157 vertically
(in at least one embodiment within a range from -2 to 2 degrees)
while one contact remains on the tibial crest till the flexion
angle is near zero.
A blinking box 156A becomes a solid line 156B box when the sensored
insert is on the tibial crest and is approximately vertical. Tibial
rotation 2300 of GUI 100 then displays the tibia crest angle. The
anatomical feature 162 of the femur and tibia are displayed in
extension when the tibia is at the measured tibia crest angle (FIG.
24). Note that the A-P (Anterior-Posterior) slope of the proximal
end of the tibia or the tibia plateau can be measured with the leg
in extension. The measurement of the A-P slope is relative to the
tibia crest. Note also that the tibia crest angle is roughly 2-3
degrees off of the mechanical axis of the tibia for a majority of
patients. A shim can be coupled to the sensored insert to adjust
height. The sensored insert can be placed in the knee joint and
coupled to the tibial tray of the tibial prosthetic component.
FIG. 24 illustrates the GUI 100 when the sensor module is placed in
the anatomical feature. In the example, the sensor module is the
sensored insert that is placed in the knee joint. The displayed
sensor system displays a value for the Tibia Rotation 2400, the
load values (e.g. lbs.), and the center of load indicators are
displayed (e.g., 158A and 158B) also referred to as the contact
points (CP). To zero the Tibia Rotation a user can then click on
the display of the Tibial Rotation 2400. The zero location can
correspond to a position designated by the user that establishes a
reference or starting position of the tibial prosthetic component.
In one embodiment, the tibial tray of the tibial prosthetic
component is aligned to a bone landmark or feature as a starting
point. Alternatively, the insert can be rotated to a predetermined
measured position and zeroed. When the sensored insert is placed in
the tibial prosthetic component the flexion value DD.D3 represents
the position in extension and the A-P slope of the tray in which
the device has been inserted. In one embodiment, the A-P slope of
proximal end of the tibia bone cut at an angle from front to back.
This A-P slope is measured by the accelerometer which changes the
flexion value 156D from extension where the sensored insert may
think the device is hyperextended. In general, a leg in extension
should measure zero degrees. The reading in box 156D is the amount
of A-P slope measured from the vertical. The user now selects or
clicks on the lettering in GUI 100 for A-P 154D. The value in box
156C that corresponds to A-P slope is transferred to box 154C or
A-P slope 154D. The flexion measurement 156D transitions to a
number near zero (FIG. 25), where the A-P value 154D is now the
negative of the flexion value or -DD.D3, or positive (since DD.D3
was negative). At this point the A-P value 154D is measured with
respect to the tibia crest. The A-P value 154D can be used to
determine the slope of the tibial plateau bone cut. The measurement
can be used to verify that the cut is correct and corresponds to
the cutting jig cutting angle for the tibia. Before the next stage
of alignment rotation values can be captured. The user can click on
the lettering CP Rotation on the GUI 100.
FIG. 25 also illustrates the GUI 100 when the tibia rotation angle
2500 is zero'd. When the Tibia rotation angle is zero'd, Contact
Point (CP) Rotation angle 2510 is displayed. Note that the Tibia
Rotation 2500 will start to indicate values from zero. A positive
CP rotation value is an external rotation (e.g., counter clockwise
rotation on the page). An external rotation is a rotation of the
device toward the lateral side. The CP rotation angle 2510 is the
angle a line through the lateral contact point and the medial
contact point makes with a horizontal plane, which is perpendicular
to the OR Table (or floor). Thus, the implant 157 image (e.g.
sensored insert), illustrating a view looking toward the head from
the knee, is rotated into the page counterclockwise, which would be
a left leg lateral rotation (hence positive CP rotation angle). As
mentioned previously, the user can position the tibial prosthetic
component and the sensored insert in a predetermined location. The
user can choose to zero at this reference position. Rotating the
tibial prosthetic component and the sensored insert from this zero
or reference position would be measured and displayed as CP
rotation 2510.
FIG. 26 illustrates the GUI 100 when the surgeon balances out the
contact points. The surgeon, at full extension or any knee flexion
angle of the limb, can try to balance the contact points on the two
articular surfaces of the sensored insert. The sensored insert has
a plurality of load sensors underlying the articular surfaces to
measure load magnitude and position of load. In one embodiment, the
surgeon can pin the tibial prosthetic component to the tibia at a
single point. This will allow the tibial prosthetic component to
rotate or pivot the tibial tray and sensored insert. Rotating the
tibial tray and sensored insert can change the point of contact on
the articular surfaces. The surgeon can use this technique to move
the contact points closer to an optimum contact position or within
a predetermined range on each articular surface. The amount of
rotation to move the contact points is indicated in the tibial tray
rotation box, the degree of parallelism of the contact points is
depicted as a degree representing the CP rotation value 2610.
Subsequent measurements of the alignment to the mechanical axis
will factor in contact point rotation in the calculations of bone
alignment. In the example, CP Rotation 2610 decreases and Tibial
Rotation 2600 increases as the device is rotated but note that a
line passing through the contact points is now more aligned with
respect to the horizontal 2640 of the display (e.g., the values of
158A and 158B are closer to each other). In one embodiment, GUI 100
can indicate a predetermined area range and compare the actual
contact points to the predetermined area range. The user would
rotate the tibial tray and sensored insert until the contact points
are within the predetermined region. Similarly, GUI 100 can
indicate a predetermined load magnitude range and compare to the
measurement of load magnitude on each articular surface. In one
example contact points 158A and 158B are also not centered with
respect to a vertical line 2630 on the GUI 100, the surgeon can
rotate to a non-zero CP rotation value FF.F2 to get the contact
points 158AA and 158B more symmetric with respect to a vertical
2630 through the center of implant 157.
FIG. 27 illustrates the GUI 100 when the surgeon clicks on the CP
rotation display to freeze the CP rotation value and the Tibia
Rotation value in the software display. When the surgeon is
satisfied with the location of the contact points he can click on
the lettering "CP Rotation" on the GUI 100, and boxes 2750 and 2760
(indicating the values are fixed) will appear near the Tibial
(tray) Rotation Value 2700 and the Cp Rotation Value 2710. The
tibial (tray) rotation angle 2700 can be used for alignment. After
this stage the alignment can begin, and the user can click on the
align button.
FIG. 28 illustrates the GUI 100 when the user (e.g. surgeon) clicks
on the alignment button 166 to initiate a measurement of
muscular-skeletal alignment. In the example, the leg is measured
and compared to a mechanical axis with the prosthetic knee joint in
place. The alignment workflow is started by indication on alignment
button 166 when the "Align" lettering on button 166 turns red and a
blue light on button 166 turns on. A Tibia Plateau Slope value 152
is displayed and an indicator dial 2800 is displayed. In the
example, the proximal end of the tibia has been cut and the tibial
prosthetic component is inserted and coupled to the tibia. The
tibial plateau corresponds to the bone cut at the proximal end of
the tibia. The tibial tray of the tibial prosthetic component
couples to and takes on an angle of the bone cut on the proximal
end of the tibia. Tibial Plateau Slope value 152 corresponds to the
medial-lateral slope of the bone cut on the proximal end of the
tibia.
A needle indicator dial 2800 moves as the anatomical feature (with
device 157) inserted therein (e.g. knee joint) is rocked back and
forth. Note that rotation is related to the values of y/x, while
tilt is related to the values of y/z. The device is rocked back and
forth until the Max-Gx value is obtained, which should correspond
to the y about 0 if the internal (not displayed) tibia (tray)
rotation is approximately zero. If the value is not zero at max A-P
axis position, then there is tilt. As mentioned previously, any CP
Rotation value can be taken into account for the calculation of
Tibial Plateau Slope value 152. During alignment (referring to FIG.
26) the axis corresponding to the A-P of the device 157 is the
vertical line 2630, while what is referred to as the Medial-Lateral
(ML) line is related to the horizontal line 2640, and there is an
axis perpendicular to both. Thus the rocking of the anatomical
feature with the device 157 inserted, is essentially looking for
the zenith of the arc of rotation, which should correspond to an ML
line orientation that should be horizontal (about 0 degrees with
respect to the horizontal on the GUI). If the angle is not zero,
there is medial-lateral slope cut into the proximal end of the
tibia that is measured and compared to the cut angle set that was
previously set in tibial bone cutting jig. Thus, verification of
the bone cut angle is achieved through quantitative
measurement.
FIG. 29 illustrates GUI 100 feedback that is provided to the user
when the leg is placed in flexion, for example 90 degrees (e.g.,
color of flexion angle text changes to yellow, indicator dial
movement 2900, when the value is approached). Note that the value
may be more than 90 degrees due to the A-P slope of the proximal
end of tibia bone cut. In general, the leg is placed in flexion
whereby the device 157 is oriented at a predetermined (chosen)
angle for example a 45 degree angle from the surface of the OR
table. Note that if the device 157 can be oriented at 45 degrees
with respect to the plane of the OR table, the orientation of the
A-P line and the normal to the A-P and M-L lines are both about 45
degrees or roughly equal in value with respect to gravity.
The knee in flexion is displayed 162 in the GUI 100. The amount the
leg is in flexion is listed under Flexion 156 of GUI 100. Display
allows the surgeon to rapidly assimilate the leg position at a
glance. In one embodiment, the tibia is pivoted on a point of the
mechanical axis. For example, the surgeon holds the heel down at
the table with one hand allowing the heel to be a pivot point (see
discussion above for FIGS. 9 and 10). With the other hand under the
knee joint the surgeon moves the knee joint inward and outward
(while pivoting about the heel contact. The patient remains in a
fixed position during the movement. As the surgeon moves the knee
joint in and out on the pivot point the indicator dial 2900 moves
and follows the motion. A delayed response of the dial 2900 with
the motion indicates that the motion is too fast, and also provides
feedback as to the rotation angle. Data is being taken to determine
the zenith values, which will determine the tilt values. Multiple
rocking past and forth about zenith is done to take data points
along each complete arc and then the points from each arc are used
to determine the location of the zenith. As the surgeon rotates the
knee joint and pivots on the heel the indicator dial 3000 (FIG. 30)
also moves to the side of rotation. For example, FIG. 30
illustrates the case where the surgeon has pivoted the knee joint
counterclockwise (as measured on the display). If during the
rotation an error occurs, the sensor module can force the surgeon
to start the flexion motion again. Similarly, if the heel
inadvertently moves during motion, and the flexion values 156 moves
away from the target, the indication of being close to the target
position (e.g., yellow text angle) can disappear (e.g., change back
to a non close indicator color such as white).
FIG. 31 illustrates the GUI 100 when the surgeon has gone back and
forth a predetermined number of times while pivoting on the heel of
the leg such that the conditions for measurement have been met. The
Mechanical Axis (HKA 150) (also referred to as the load bearing
axis) alignment number is now displayed and frozen, as is the Tibia
Plateau Slope 152. The HKA or mechanical axis 150 of the display is
a measure of the total offset of the femur and tibia to the
mechanical axis. There is clinical evidence that indicates that
misalignment of a prosthetic joint to the mechanical axis above a
predetermined amount will result in joint performance loss and
long-term reliability issues. Moreover, as prosthetic component
design becomes more sophisticated surgeons can add predetermined
slopes to the bone cuts to enhance performance. The system can be
used to verify the angle of the bone cuts and the trial prosthesis.
Thus, a measurement of the tibia alignment to the mechanical axis
has been measured. GUI 100 will display an offset in degrees that
is either varus or valgus to the mechanical axis.
FIG. 32 illustrates the GUI 100 when the surgeon begins to measure
an offset of the femur to the mechanical axis. In one embodiment,
the leg is placed in full extension and lifted to pivot on the
femoral head of the femur in the hip joint. The surgeon lifts the
leg in full extension 3200 at an angle 3210 that places the
sensored insert in the knee joint at approximately 45 degrees to
the surface of the OR table. In one embodiment, mechanical axis
value 150 disappears from GUI 100 as the femur offset is being
measured.
FIG. 33 illustrates that as the surgeon gets close to the target
position, feedback is provided (e.g., the text of the flexion angle
156 changes, referred to as device color). For example if the
target is -45 degrees the color of the text will change when the
sensored insert angle approaches -45 degrees within +/- a few
degrees in the knee joint. Thus, the femoral offset to the
mechanical axis can be measured upon reaching the appropriate angle
for the sensored insert (e.g., -45 degrees) with the leg in
extension.
With the leg in extension (see FIG. 28) the knee joint is then
rotated back and forth pivoting on the hip joint a predetermined
number of times. Similar to the measure of the tibia offset, data
points are measured over each arc created by the knee joint and the
data points are used to determine a zenith or Max G of the arc. The
position of the Max G of the arc of the knee joint is used to
calculate the medial-lateral slope of the distal end of the femur
surface. The femoral offset is measured in degrees and can be varus
or valgus to the mechanical axis of the leg. GUI 100 displays the
combined offsets of the tibia and femur to the mechanical axis. In
one embodiment, the measured femur medial-lateral slope is
subtracted from the tibia medial-lateral slope values to obtain an
offset value 3280 that is displayed in mechanical axis 3270. Once a
measured value average is obtained the color of the text in
mechanical axis 3270 changes to match the text of the other
indicators (e.g., A-P) and a box 3290 appears around the offset
value 3280 in mechanical axis mechanical axis 3270. The angular
accuracy obtained by at least one embodiment is on the order of 0.5
degrees for navigation and at least one embodiment can obtain
greater than 0.1 degree accuracy.
In FIG. 34, the GUI 100 displays when the surgeon repositions the
leg to obtain a new target flexion angle value. In one embodiment,
a HKA or mechanical axis value 150C disappears, while maintaining
again the measured Tibia value 152. In this example the knee
position 162B alignment target is a flexion angle 156 of 45
degrees. As the surgeon is approaching the target flexion (e.g., 45
degrees also referred to as a mid flexion target) feedback is
provided, for example the flexion angle text 156 changes to a
device color. If the surgeon has moved outside the target flexion
value the indicator text color changes. When the surgeon is back
within the target window about the third flexion target angle
(e.g., 45 degrees), the text displays the angle in the device
color.
The discussion above is for a non-limiting embodiment that
discusses the alignment of a device (sensor) 157 placed into an
implant. Note that the sensor 157 can also be placed into a cutting
jig 3530. The cutting jig 3530 (FIG. 35) is coupled to the bone, as
described below to define one or more bone cut angles. The device
157 can be used to align cutting jig 3530 to precisely cut bone
angles relative to the mechanical axis. It is used similarly as
described hereinabove to measure femur and tibia offset to the
mechanical axis. The measurements can then be taken into account in
aligning cutting jig 3530 to specific bone cuts. Thus, bone cuts
can be made using quantitative measurements using a conventional
bone cutting jig in conjunction with the system disclosed
herein.
In one embodiment, device 157 is a sensored insert. A shim can be
coupled to the sensored insert. The shim can have a tab extending
from the shim body that couples into a cutting slot of cutting jig
3530. Alternate variations can also be used to affix the sensored
insert and shim to the cutting jig 3530. Cutting jig 3530 is
attached to a bone. FIG. 35 illustrates bone cutting jig 3530
coupled to the tibia of the leg. The sensored insert is referenced
as disclosed above prior to coupling the sensored insert to bone
jig 3530. For example, the device 157 can be zeroed to a plane of
the operating table. Similarly, device 157 is zeroed to a plane
perpendicular to the operating table. The leg is then placed in an
approximate position of extension. The insert is coupled to a bone
landmark or tool coupled to the leg. For example, the distal end of
device 157 is held against and referenced to the tibial crest as
disclosed above. In another fashion, the jig can be inserted in the
knee with the attached sensor, and the pre-cut slope of the
proximal tibia plateau can be referenced.
Once referenced, device 157 can be coupled to a cutting jig to
measure alignment. Cutting jigs are typically coupled and aligned
to a bone in a predetermined manner identified by the manufacturer
of the jig. The jig can have a cutting slot for fitting a saw to
cut the bone at a precise angle. The cutting slot of the cutting
jig can be precisely moved to change the angle of the cut from a
reference position of the jig. In one embodiment, cutting jig 3530
coupled to the tibia is referenced to make a cut with zero
medial-lateral slope and zero anterior-posterior slope to the
proximal end of the tibia. The cut can be a simple cut along a
single plane or a compound bone cut across multiple planes. The
shim that couples to the bone jig can be customized for fitting a
specific jig. The manufacture of the shim has a substantially lower
cost than device 157. This allows device 157 to be used for a wide
variety of different jigs and prosthetic components without costly
modification.
In one embodiment, the shim couples device 157 to bone cutting jig
3530 such that device 157 is in alignment to the cut to be made in
the tibia. As mentioned previously, the device has been zeroed and
referenced similar to the example when the sensored insert is
installed in the knee joint to verify alignment and bone cuts. The
process of measuring the alignment of the tibia relative to the
mechanical axis and the femur relative to the mechanical axis is
also similar to that disclosed above for the sensored insert in the
knee joint. The leg is placed in flexion such that device 157 is at
a 45 degree angle to the surface of the operating table. The heel
of the leg is held against the operating table while device 157 is
positioned. The heel is held at the position where device 157 is at
a chosen angle, for example a 45 degree angle as a pivot point for
the knee joint. The knee joint is rocked back and forth pivoting
off of the heel. The ankle can be held to prevent movement in
relation to the heel. The system measures points of the arc as the
knee joint is rocked back and forth (see discussion with respect to
FIG. 28). The knee joint is rocked back and forth a predetermined
number of times. The system calculates the location of the Max-G
point of the arc. The system then calculates the medial-lateral
slope of the proximal end of the tibia from the location of the
measured Max-G position relative to the Max-G position for the
tibia aligned to the mechanical axis. The calculated medial-lateral
slope corresponds to a varus or valgus offset or angle of the tibia
relative to the mechanical axis. The surgeon utilizes the
quantitative measurements to adjust bone cutting jig 3530 to set
appropriate bone cut angles for A-P slope and M-L slope taking into
account the patient anatomy and the specific prosthetic components
being used. The tibial prosthetic component can be installed after
the bone cut has been made and angles re-checked.
FIG. 36 illustrates two bone cutting jigs that are used on opposing
bones (e.g. femur and tibia) of a muscular-skeletal joint. In the
example, jig 3530 is coupled to a proximal end of the tibia and a
jig 3630 is coupled to a distal end of a femur. Device 157 can be
coupled to either cutting jig as disclosed above. Although
disclosed hereinabove, the system provides the option of cutting
the femur or the tibia first. The A-P slope can be captured. Note
the process is similar to that described above, for example the 90
degree bent knee can now be rocked multiple times except the
movement is to obtain a near zero value of the tibia angle 3510.
When the user has a tibia angle close to zero the tibia select
button 3540 is pressed to switch to the femur, and the jig on the
tibia is locked in place. The process is then repeated for the
femur jig 3630, see FIG. 36, where the femur select button is
showing 3640, and the object is to zero the femur value 3610. Now
the distal femur and proximal tibia can be cut.
Additionally the device can be placed on the tibia plateau of a cut
distal face. The sensor can be pinched in place until the loading
is even, and used to mark aligned drill holes to place a cutting
jig.
As described above at least one embodiment can be used to make bone
cuts. Herein we described a non-limiting example of an embodiment
used to cut bones for installation of a prosthetic knee joint,
although the embodiment is not limited to any particular joint or
bone. The system can be used to make any bone cuts of the
muscular-skeletal system. In this description the assumption is
that a user has launched or re-launched the GUI as disclosed
hereinabove. The GUI can provide feedback for zeroing the device.
In at least one embodiment zeroing the device will include a flat
(horizontal) orientation with respect to a surface (e.g., table),
and a vertical orientation with respect to the surface of the
table. Feedback may include a tone, and/or text on the GUI, for
example the GUI may display the text "Please rotate the device 180
degrees and re-position it flat on the table--press the "Zero"
button again."
FIG. 37 illustrates the bones of a knee 3720 and a device 3700
(e.g., insert sensor), where the device 3700 is placed flat 3730
(e.g., about parallel with the surface of the table) upon the table
3710 for zeroing. The feedback will then instruct the user to move
the device 3700 into a vertical orientation for zeroing. For
example the GUI may display the text "Please position the device
vertically--press the "Zero" button again". Device 3700 includes a
plurality of sensors for measuring a parameter of the
muscular-skeletal system. Device 3700 can be in the form of a
prosthetic component for trial or permanent measurements. In the
example, device 3700 is a sensored insert having a plurality of
load sensors underlying each articular surface and at least one 3
axis accelerometer for measuring position, rotation, and slope (or
tilt).
FIG. 38 illustrates the bones of a knee 3720 and a device 3700
(e.g., insert sensor), where the device 3700 is placed vertical
3740 (e.g., about perpendicular with the surface of the table) upon
the table 3710 for zeroing. Once the device is zero'd the GUI can
indicate that to the user (e.g., via text) and the device can be
moved into the sterile field. Note that the zeroing can be done on
a back table and transferred into the sterile field.
Once zero'd the device can capture the tibia in a reference
position as described above. For example, the leg is positioned in
extension or approximately in extension. The same technique as
described above can be used to capture a bone landmark such as the
tibia crest (FIG. 39). The device 3700 is placed on the tibia crest
(note here the bone is showing, whereas in actual practice the
device can be place upon the skin above the tibia) resulting in an
axis 3910 running through the bisector axis (same axis as the
vertical axis in FIG. 38 when zero'd vertically), where the axis
3910 is approximately perpendicular with respect to the plane of
the surface of the table. Once the reference position is captured
the GUI may provide feedback, for example the GUI may display the
text "The Reference captured". Place the device in tibial
prosthetic component tray". In extension, click A-P indicator to
capture A-P slope".
Once the tibia crest is captured and the leg is in full extension,
a cutting jig, either individually or in relation to each other can
be coupled to the bones for cutting bone surfaces at precise angles
for receiving prosthetic components. The process for finding
alignment relative to the mechanical axis can similarly be
identified as disclosed herein above only with device 3700 coupled
to a bone cutting jig. The supports precut alignment of the cutting
jigs to the mechanical axis. In the non-limiting knee example the
proximal tibia and the distal femur can be cut. The cutting jig can
be a commercial jig and need not be a specialized cutting jig when
using the techniques described herein and an adapter to couple
device 3700 to the commercial jig.
FIG. 40 illustrates at least one example of a method of connecting
the device 3700 to the cutting jig 4200 via an adapter 4000.
Adapter 4000 can be a low cost shim that couples to device 3700. In
one embodiment, adapter 4000 has a tab or tongue that extends from
the shim body. The tab of shim 4000 fits into a cutting slot of a
cutting block. In the example, different adapters can be made for
different cutting blocks allowing easy adaptability to various
prosthetic component systems.
FIG. 41 illustrates the combined device 4100 including the adapter
4000 and the device 3700. In one embodiment, adapter 4000 and
device 3700 have corresponding features that couples adapter 4000
to device 3700. In the example, the features allow adapter 4000 to
be removed from device 3700. For example, adapter 4000 can have
corresponding lips or flanges that couple together by interference
or by connector.
FIG. 42 illustrates the insertion of the combined device 4100 into
a cutting jig 4200 that is capable of accepting the combined device
4100, forming a cutting system 4300. The tab extending from the
adapter 4000 fits into a receiving portion 4215 of cutting jig
4200. In the example, receiving portion 4215 of cutting jig 4200 is
a cutting slot. The tab fits into the slot and is retained by
cutting jig 4200. The tab also maintains an alignment of device
3700 to cutting jig 4200.
FIG. 43 illustrates the device 3700, adapter 4000 and cutting jig
4200 coupled together. The cutting system 4300 can now use the
alignment information of the device 3700 to reference bone cuts.
The tab of adapter 4000 is inserted into receiving portion 4215 of
cutting jig 4200 to retain and align device 3700 to cutting jig
4200. In one embodiment, the posterior portion of device 3700
couples to a surface of bone cutting jig 4200.
FIG. 44 illustrates the cutting system 4300 coupled to the extended
leg. In the example, system 4300 is coupled to the tibia in
preparation of cutting the proximal end of the tibia to receive a
tibial prosthetic component. As mentioned previously, system 4300
was referenced to a tibia reference (e.g. tibial crest). System
4300 will measure the A-P slope of the bone cut with the leg in
extension. The bone cutting jig can be adjusted to change or modify
the A-P slope of the bone cut.
The leg is then placed in flexion (FIG. 45) where a plane defined
by the joint passes through about a vertical 4500. The position of
flexion is selected where the accelerometer in system 4300 is at a
45 degree angle to the referenced surface (e.g. the operating
table). The heel of the leg is held at the position achieving the
45 degree angle. As previously described above the joint 3720 can
be rocked back and forth 4510 with the cutting system 4300 on the
joint as it is rocked. The knee joint is pivoting on the heel of
the leg. System 4300 measures the Max-G of the arc created by the
rocking motion. The position of the Max-G in conjunction with the
leg anatomy is converted to a measurement of the tibia offset.
Using the measurement information the cutting system 4300 can
adjusted 4520 to change or modify the vargus and valgus tilt of the
proximal end of the tibia. In one embodiment, system 4300 is
fastened to bone with bone screws prior to measurements being
taken. System 4300 can have an adjustable cutting slot thereon that
can change or modify the A-P slope and M-L slope of the jig. In a
second embodiment, system 4300 can be partially fastened to bone
allowing the jig and thereby the cutting slot to be moved and
pinned for the bone cut after the measurements have been taken and
adjustments made. In a third embodiment, system 4300 can be
temporarily fastened to the bone allowing the measurements to be
made. The cutting jig can be adjusted after measurements have been
made to cut the appropriate bone slopes. The cutting jig can then
be fastened to bone prior to making bone cuts with a bone saw.
As mentioned previously, since cutting system 4300 is referenced to
the tibia reference an A-P slope can be obtained. For example FIG.
46 illustrates an extended joint where the cutting system 4300
cutting slot is moved 4620 to obtain a desired A-P slope. Note that
the illustration in FIG. 46 shows cutting system 4300 on the tibia,
however the same process as described above can be used on the
femur. For example instead of the A-P slope one would obtain the
distal-femur flexion angle.
FIG. 47 illustrates a bone cutting system 4700 on a distal end of a
femur and a bone cutting system 4300 on a proximal end of the
tibia. Moreover, measurements can be taken on the femur and the
tibia to adjust cutting systems 4300 and 4700 to achieve parallel
bone cuts. In one embodiment, the measurement device is moved from
the system 4300 to system 4700 or vice versa to take measurements.
The leg is placed in extension and verified by systems 4300 or 4700
depending upon which has the measuring device. For example, system
4300 is coupled to the proximal end of the tibia, the tibia
measurement is selected on the GUI, the A-P slope of the proximal
end of the tibia is measured, and the A-P slope of system 4300 is
adjusted for cutting a predetermined A-P slope. Similarly, the
measuring device can be transferred to system 4700. System 4700 is
coupled to the distal end of the femur, the distal femur flexion
(e.g. A-P slope) is measured at the distal end of the femur with
the leg in extension, and the distal femur flexion is adjusted for
cutting a predetermined A-P slope. In one embodiment, the bone cuts
on the distal end of the femur and the proximal end of the tibia
are set on the cutting blocks to be parallel to one another. This
can be done very accurately because the bone cut settings use
quantitative measurements from the measurement device referenced to
the same plane.
The offset of the femur and tibia relative to the mechanical axis
is also measured with systems 4300 and 4700. The femur and the
tibia are respectively pivoted on the femoral head and the heel of
the leg as disclosed herein. Data points are taken over several
arcs as the knee joint is rocked back and forth a predetermined
number of times. The Max-G point is located for the tibia pivoting
on the heel and a varus-valgus offset is calculated. Similarly, the
Max-G point is located for the femur pivoting on the femoral head
of the femur and a varus-valgus offset is calculated. The
information can be used to adjust the medial-lateral slope of the
bone cut for the distal end of the femur and the proximal end of
the tibia.
Thus, two cutting systems 4300 and 4700 can be used to get the
desired distal femur flexion angle 4720 for the femur cutting
system 4700 and the desired A-P angle 4620 for the tibia cutting
system 4300, while orienting the cutting systems 4300 and 4700 so
that they are parallel. Furthermore, systems 4300 and 4700 can
measure the vargus/valgus tilt relative to the mechanical axis for
the femur and tibia. The surgeon can use the measurement data from
systems 4300 and 4700 to set the medial-lateral bone cuts on
respectively the proximal tibia and distal femur. Note that as
described above the vargus/valgus are measured with respect to the
mechanical axis, where the mechanical axis is not the anatomical.
The cutting systems 4300 and 4700 are coupled to the distal femur
and the proximal tibia with the adjusted cutting slots based on
quantitative measurements. A bone cutting saw is then used to but
the femur and tibia. Note that both cutting systems 4300 and 4700
can be aligned with regards to any axis. In the embodiment
described both cutting systems 4300 and 4700 were aligned to the
tibia crest, thus ultimately to an axis of the tibia, however one
could choose a femur axis to reference as well.
In addition to making initial cuts one can use the system to make
additional cuts. For example the lateral femoral condyle can roll
back on the tibia plateau causing unwanted lifting on the lateral
side thereby placing all or most of the loading on the medial
condyle as the knee is placed in flexion. The cutting jig is
typically placed back on the distal femur, which already has a
first cut. Occasionally, a second cut is made to adjust the angle
of the femoral insert/component by cutting the posterior condials
of the distal femur. The second cut is made by a special cutting
jig that has some cut rotation built into the cut to compensate for
the lift off in flexion. At least one embodiment can be used to
increase the accuracy of the second cut. For example a femoral
rotation guide can be placed upon the first cut with a device
inserted to orient a cutting jig optimally for the second cut.
FIG. 48 illustrates a femoral rotation guide 4800 where two condial
surfaces 4840A and 4840B can pivot 4860 about an axis 4850 when
pinchers 4810A and 4810B are squeezed or extended away from each
other 4820. The condyle surfaces 4840A and 4840B are placed upon
the cut condyles of the distal femur, and attached to the posterior
uncut condyles of the femur. Note that the femoral rotation guide
4800 can be inserted with the patella reduced to provide realistic
loading, and information regarding patellar tracking while
rotational adjustments are made. At least one reference hole 4870
is available so that once the correct orientation is obtained.
Reference holes for the cutting jig can be drilled into the bone.
The femoral rotation guide 4800 can be removed and a cutting jig
placed on the bone to be cut at an optimal rotation that supports
both condyles contacting each articular surface over a range of
motion of the knee joint. The cutting jig is lined up with the
reference holes and screws inserted therein to fasten the device
down.
FIG. 49 illustrates the femoral rotation guide 4800 attached to the
distal end of the femur 4900, with the device 3700 inserted into a
tibial tray 4910 or placed on the tibia plateau cut. The assembled
components allow the leg to be moved through the range of motion.
It is important to note, that the patella 4920 is moved in-place
and the loading observed, rotating the knee joint to determine if
condyle surfaces 4840A and 4840B are loading device 3700 over the
range of motion (e.g., load sensor tibial insert). Note that FIG.
49 shows the system in separated view however when measuring the
loads the condyle surfaces 4840A and 4840B will be in contact with
device 3700. In one embodiment, after the proximal tibia and distal
femur are cut, the leg is taken into extension. By knowing that the
condylar geometry of the jig is the same as the distal femur, and
the tibial sensor has the same geometry as the tibial component,
the knee is extended and rotation of the femoral and tibial jigs
can optimize implant congruency in extension, then soft tissue
balancing can be performed to balance the "extension gap". The leg
is now placed in flexion and pinchers 4810A and 4810B are squeezed
together such that posterior femoral condyles 4840A and 4840B
shift, translate or rotate to engage the condyles of the
corresponding Tibial articular surface. The loading can be viewed
on the GUI. When the loading on both articular surfaces of device
3700 are at an appropriate level or within a predetermined load
range then dial 4830 is used to lock the pinchers so that the
rotation 4860 is locked, and AP translation defined. Reference
holes 4870 can then be drilled for subsequently mounting the
cutting jig. Thus in summary, the pinchers 4810A and 4810B are
pinched 4820 resulting in rotation 4860 of the condyle surfaces
4840A and 4840B thereby changing the loading measured by the device
3700. The angular orientation of the femoral rotation guide 4800 is
locked and the reference hole drilled when a correct loading over
the range of motion has been found. This process can be performed
having all the muscular-skeletal joint anatomy in-place for correct
kinetic loading. The cutting jig can then be aligned with the
drilled reference holes and used to make the chamfer cuts and A-P
cuts. Note that in this embodiment the femoral rotation guide can
be a disposable system, and used to measure loading with the
patella in place moving the leg in flexion and/or extension.
At least one embodiment is directed to a novel sensor system that
incorporates positional sensing, load sensing, RF communications,
powering and telemetry in a footprint of a tibial trial. This
footprint is miniaturized to allow incorporation of the trial
insert into other instruments that are utilized during a knee
procedure such as gap balancers, distractors, and cutting jigs or
can be molded to fit into any orthopedic system (e.g., knee
system). The sensor system can also be placed in the tibial
prosthetic component or the femoral prosthetic component.
Furthermore, the design is not limited to measurement and alignment
of the knee but can be used for hip, spine, ankle, shoulder, elbow,
hand, wrist, foot, bone, and the muscular-skeletal system. Note
that the sensors used in the sensor system are not limited to any
particular type of sensor for example the sensor(s) can be
capacitive, ultrasonic, film sensing, accelerometers,
inclinometers, gyroscopes, acoustic, and electromagnetic.
At least one embodiment is also directed to a sensor system that
communicates intra-operatively with real time data to a GUI that
can be interpreted by the surgeon. This GUI can represent data from
the sensors, can be voice activated and controlled, can integrate
other data for display such as IR/US navigation systems for
incorporated data points. Can record surgical footage with time
stamped sensor data, can incorporate data related to the patients
pre-op/intra-op/and post-op data. Implant data can be captured,
which can be sent to a cloud computing system for access. At least
one embodiment is directed to a sensored system composed of a trial
insert that: can be used as a standard trial with no utilization of
the electronics; can be utilized prior to cutting the bone to give
angular/positional information of proposed cut angles; can be
utilized after the cuttings jigs are attached to the femur and
tibia to confirm appropriated angular positioning for the cut; can
be utilized after the bony cuts have been made to check the
accuracy of the angular cuts; can obtain a plane (such as the
tibial crest) which the sensors can now reference to, to provide an
angular number for interpretation to reference to before or after a
cut is made; can incorporate other data points from other
instruments (IR/US/Magnetic) on the GUI to incorporate information
for interpretation; can incorporate angular information and load
information with the knee implant trials in, which can allow the
surgeon to refine the angular cuts and/or soft tissue balance,
and/or implant position and rotation real time to optimize the leg
alignment as defined by the surgeon; can give real time data as to
how angular geometry of the bony cuts/angles or the implant
geometry affects soft tissue balance/loads and implant kinetic
function; can give real time data as to how the soft tissue tension
affects the overall mechanical alignment of the leg, and the
implant kinetic function; can give real time data as to how
adjustments to the bony angles and soft tissue tension affect each
other in a dynamic function and affect collectively or
independently the kinetic knee function; can be used with a trial
implant system or a final implant system prior to closing the
joint; can utilize a reference angle/plane that can be changed
intra-operatively at the discretion of the surgeon; can give
information related to implant congruency, alignment and soft
tissue balance with thicker trial inserts, and/or angular insert
change; and can utilize incorporation of pre-operative scans such
as x-rays, CT scans, MRI's into the GUI to reference intra-op
planes and angles to. The Tibial and or Femoral cuts can be made
first, then the Secondary femoral or Tibial cut can be made by
knowing the angular reference of the interposed cutting jig to
obtain equal extension gaps and flexion gaps. It allows distance
gap measurements to incorporated soft tissue tension in multiple
knee angles.
In addition to utilizing the sensor 3700 on the tibia crest 427, at
least one embodiment 5000 (e.g., reference position tool), FIG. 50,
utilizes a sensor 3700 on a tibial alignment device/tool 5010 to
obtain the alignment information discussed herein with reference to
FIGS. 4 and 39, where the alignment device 5010 and the sensor 3700
move as one as did the sensor 425 on the tibial crest 427 in FIG.
4. For example the tool 5010 (with sensor 3700 attached) is rotated
back and forth in the same manner as the device 3700 on the tibial
crest to obtain alignment information as in the discussion with
reference to FIGS. 4 and 39. In this particular embodiment the
sensor 3700 and alignment device 5010 move together, where the
alignment device 5010 is positioned so that one end 5025A is
approximately aligned 5010A with the proximal end 5020 of the
tibia. The opposite end 5025B of the alignment device 5010 is
approximately aligned with the distal end 5010B of the tibia
5030.
FIG. 51 illustrates a different view of the device shown in FIG.
50. The alignment device 5010 is extendable so that the ends 5010A
and 5010B are moveable to fit any leg or the tool/alignment device
5010 can comprise more than one tool having several different
lengths. At least one embodiment is adjustable to any length needed
for example FIG. 51 illustrates an adjustable 5040 alignment device
5010. For example the section 5010 D can be attached to a slightly
smaller bar 5010E that slides into a slightly large similarly
shaped channel 5010F. The alignment device 5010 can be manufactured
out of many different types of medical grade material (e.g.,
stainless steel, bio-compatible plastic). The alignment device 5010
can include an arm 5025 that contacts with the relative positions
5010B and 5010A where the arm 5025 extends from the body 5012. Note
that the sensored device 3700 can be a prosthetic component.
At least one embodiment is directed to a muscular-skeletal
alignment system 5000, that includes: a sensored device 3700
including at least one 3-axis accelerometer for measuring position,
rotation, and slope; a remote system 5090, coupled to the device
(e.g., wired or wirelessly 5095) for receiving position, rotation,
or slope data; and a tool (e.g., alignment device 5010) configured
to couple to the muscular-skeletal system where the tool is
configured to be positioned to generate a reference with the
sensored device 3700 coupled thereto. The tool/alignment device
5010 can include a tab 5031 so that the sensored device 3700 can be
inserted onto the tool/alignment device 5010 and the sensored
device 3700 can include a slot to accept the tab 5031.
FIG. 91 illustrates one possible configuration of axes with
sensored device 3700, where the initial orientation of the sensored
device 3700 lies in the x-y plane, and the z-axis is normal to the
x-y axis in accordance with the right-hand rule. For example where
the body axes of the sensored device 3700 (x-s, y-s, z-s) initially
are aligned with the reference axes (x, y, z). When the sensored
device is then moved out of alignment with the reference axes (x,
y, z) the orientation of the sensored device body axes (x-s, y-s,
and z-s, can be projected onto the reference axes (x, y, and z) to
obtain Dx, Dy, and Dz. These in turn can be used to define tray
rotation, varus, valgus, flexion and slope. For example tray
rotation can be defined as arctan(Dy/Dx), Varus and Valgus can be
defined as arctan(Dy/Dz), and Flexion and Slope can be defined as
arctan(Dz/Dx.).
FIG. 92 illustrates a plot of the x-acceleration value (e.g.,
obtained by an accelerometer) versus angle of inclination .theta..
As can be seen there is a region of linearity 9100, valid within a
range of acceleration (e.g., -0.8 to 0.8 g) and angle of
inclination (-45 degrees to +45 degrees). The angle of inclination
can be defined as the inverse tangent of the ratio of (axout/ayout)
or the ratio of the x acceleration value to the y acceleration
value.
FIG. 93 illustrates a bent leg (sometimes referred to as a bent
knee), with a sensor 9315 oriented at an angle, for example 45
degrees with respect to axis of rotation 9370A. Note other
references can be used to define the angles of sensors. The
knee/leg can be defined by the femur axis 9310A and 9310B, and
tibia axis 9320A and 9320B. The knee can be rotated about the hip
center 9330 and the "virtual" pivot point 9340 to obtain the
mechanical axis 9300. Intersection of the two planes 9380 and 9390
defines the axis of rotation, which is along the load bearing,
mechanical axis 9300. Plane 9380 is defined by femur axis 9310B and
tibia axis 9320B, plane 9390 is defined by femur axis 9310A and
tibia axis 9320A. The femur axis (9310A and 9310B) is offset 9360
with respect to the hip center 9330. The rotation moves the knee
middle 9371 from 9370A to 9370B equivalent to the plane 9390
rotating to position 9380. One of the pivot points of the leg is
the heel 9345, while the femur axis (9320 A and 9320B) passes
through the center of the ankle 9350A and 9350B respectively to the
"Virtual Pivot" 9340 that falls in line with the Heel 9345 and Hip
Center 9330, defining the Axis of Rotation 9300. Note that the
virtual pivot 9340 can lie above or below the plane 9342 (e.g.
table).
To obtain the mechanical axis (MA) the Tibia-V is obtained by
rotation on hip center 9330 and heel 9345 and capturing the a y/z
value at the maximum x-value (e.g., maximum of the arc), as
measured by the sensor 9315. The distal Femur-V value is obtained
by lifting the leg in extension to a position where a sensor in the
knee is upside down but still at 45 degrees, and rotating on the
hip center 9330 to capture a new y/z value at the maximum x value
as measured by the sensor 9315. Then the Mechanical axis can be
defined as MA=(Tibia-V)-(Distal Femur-V).
FIGS. 94A and 94B illustrate two positions that can be used to
average x and y positions to minimize error in the x-y reference
plane. For example, a sensor 3700 can lie on a table 9400 and be
rotated (from FIG. 94A to 94B). FIG. 95 illustrates a vertical
position (of sensor 3700 x-s axis with table 9400) that can be used
to average y again to minimize errors (e.g., internal assembly
position of the accelerometer) and to average z.
Thus as discussed, one can calculate alignment to the mechanical
axis by rotating back and forth on the pivot points. Note that the
sampling rate of the sensor can vary for example a sample rate at
15 times/second when getting data points on the arc can be used. As
discussed depending on the position of the max X (maximum of the
arc) one can identify the tilt (Y/Z) of the bone cut
(medial/lateral) which corresponds to the Varus/Valgus of the bone
to the mechanical axis. Note that rotation back and forth can
continue until one get measurements that are within a 1/2 degree of
the average.
FIG. 90 illustrates at least one embodiment that is directed to a
method 9000 of generating a reference position comprising the steps
of: 9005 coupling a device 3070 having a three-axis accelerometer
to a reference position tool 5010; 9010 placing a muscular-skeletal
system in a predetermined position; 9020 positioning the reference
position tool 5010 to at least one muscular-skeletal landmark of
the muscular-skeletal system; 9030 aligning one plane (e.g., 5010A
or 5010B) of the device within a predetermined alignment range; and
9040 measuring a position, rotation, or tilt of the reference
position tool at the predetermined position. A further embodiment
includes a step 9050 of adjusting a length (e.g., 5040) of a body
of the reference position tool. A further embodiment includes 9060
clipping the device to a body of the reference position tool. A
further embodiment includes a step 9070 of contacting the
muscular-skeletal system with a first and second arm of the
reference position tool where the first and second arms extend from
a body of the reference position tool.
Note that the non-limiting description describing aspects of the
invention for use in a total knee replacement (TKA) surgery, the
invention is not limited to TKA but can be used in orthopedic
surgery in general or for any joint repair, spine surgery, bone, or
portions of the muscular-skeletal system that incorporates bony
cuts and soft tissue balance for an optimized outcome, with or
without implants.
Additional Embodiments
Additional non-limiting examples of embodiments will be discussed
herein.
FIG. 52 illustrates at least one embodiment 5299 is directed to
methods and devices using kinetic measurements for joint alignment.
For example at least one embodiment 5200 is directed to a method of
measuring joint alignment between first (e.g., femur) and second
bones (e.g., tibia) comprising the steps of: positioning a joint to
a target flexion value (e.g. a chosen knee bent) as measured by a
sensored module within the joint 5210; rotating the joint 5220
between a first point and a second point where the first and second
points are on opposing sides of the joint 5220. For example
referring to FIG. 1A the first point can be along path 102A, while
the second point is along 101A and the act of rotating is moving
along the paths 101A and 102A. For example, as displayed in FIG.
53, 5310 the first point can be about 45 degrees medially along
101A measured with respect to the vertical axis 100A, while the
second point can be about 45 degrees laterally along 102A measured
with respect to the vertical axis 100A. A first alignment value is
saved 5230, where the first alignment value is related to the
position of the first bone, for example the first alignment value
can be the angular relationship between an axis along the first
bone and the tibia crest 345. Then positioning 5240 the joint to a
second target flexion value (e.g., moving a leg to extension). When
the joint is at the second target flexion value the joint can then
be rotated back and forth to obtain the alignment of the second
bone. For example one can rotate 5250 the joint about a third point
and a fourth point where the third and fourth points are on
opposite sides of the joint, for example with the leg in extension
the leg can be rotated along the path 101A and 102A with a pivot
point at the heel to acquire the second alignment value. The second
alignment value is saved 5260 (e.g., computer readable memory),
where the second alignment value is related to the position of the
second bone, for example the second alignment value can be the
angular relationship between an axis along the second bone and the
tibia crest 345. The first and second alignment values can be used
by a processor to calculate alignment 5270 of the first bone with
regards to the mechanical axis and/or calculate the alignment of
the second bone (e.g., angle between an axis through the second
bone and the mechanical axis) with regards to the mechanical axis.
Note that alignment can be with regards to other axes, for example
the tibia crest 345 instead of the mechanical axis.
Note that the rotation 5280 between the first and second points or
the third and fourth points 5290 can be about a pivot point for
example the heel or some other chosen pivot point, where the pivot
points for either can be different but relate to the mechanics of
the joint. Note that the process of alignment can use a sensor as
described above, where the sensor can be zero'd 5295 with respect
to a first reference plane and a second reference plane (e.g.,
horizontal, vertical planes). For example as described above the
horizontal plane can be a table top and the vertical plane
perpendicular to the table top.
Note that during rotation, measurements 5330 can be taken along the
paths (e.g., along 101A and 102A). The amount of measurements
depends on the sampling rate and the speed of rotation. The
measurements can be used by the processor to calculate 5340 the
maximum of the arc of motion, for example the highest point above
the table.
In addition to alignment the measurements can be used to calculate
a tilt value 5350 that is related to vargus or valgus misalignment.
For example the measurements 5360 can determine the angles 193A or
195A, which can be measured with respect to various axis (e.g.,
mechanical axis, tibia crest).
Note that the sensor can determine flexion position, for example
prior to rotation between the third and fourth points the sensor
can provide feedback to a user to flex the joint until an axis of
the sensor acquires a desired orientation, for example the
horizontal plane of the sensor intersecting the table plane by an
angle (e.g., 45 degrees).
FIG. 54 illustrates steps according to an embodiment where the
vargus/valgus angle of the first bone can be compared to the
vargus/valgus angle of the second bone to calculate 5370 the
alignment of the first and second bones to a reference axis (e.g.,
mechanical axis, tibia crest).
FIG. 55 illustrates a block diagram of at least one embodiment is
directed to a method of measuring alignment 5500 of a tibia to a
mechanical axis or a tibia crest of a leg which includes the steps
of: placing a heel 5510 of a leg in an approximately fixed
location; positioning a knee joint 5520 to a target flexion value
as measured by a sensored insert coupled within the knee joint;
rotating the knee joint 5530 between a first point and a second
point (e.g., as described above), where the first and second points
are respectively on a medial and lateral side of the knee joint,
and where rotating the knee is pivoting on the heal of the leg; and
saving an alignment value 5540 of the tibia. Additional
embodiments, as illustrated in FIG. 56, can further include a step
of maintaining an ankle in a fixed position 5610 relative to the
heel. Additional embodiments can further include a step of
positioning the knee joint 5620 where the sensored insert (e.g., an
insert with sensors) is at approximately a 45 degree angle.
Additional embodiments 5690 can further include the steps of
rotating the knee joint 5630 between the first and second points at
least two times; measuring data points 5640 over an arc of the
anterior-posterior axis; and determining a maximum of the arc 5650
(e.g., as discussed above).
Additional embodiments, for example as illustrated in FIG. 57, can
further include the steps of calculating a tilt value 5700 of the
sensored insert along a medial-lateral line (e.g., in direction 101
and 102 respectively) of a proximal end of the tibia; converting
the tilt value 5710 to a varus or valgus number in relation to a
mechanical axis or a tibia crest of the leg for the tibia.
Additional embodiments 5800, for example as illustrated in FIG. 58,
can further measure the alignment of the femur, for example the
process can include the steps of positioning a knee joint 5810 to a
target flexion value (e.g., so that the leg is bent or in
extension) as measured by a sensored insert coupled within the knee
joint; rotating the knee joint 5820 between a first point and a
second point, where the first and second points are respectively on
a medial and lateral side of the knee joint, where rotating the
knee is pivoting on a hip joint of the leg; and saving an alignment
value 5830 of the femur.
Note that additional embodiments, for example as illustrated in
FIG. 59, can include positioning the knee joint 5910 to various
orientations for example where the sensored insert (e.g., coupled
to the knee) is at approximately a 45 degree angle or positioning
the leg 5920 in extension.
Additional embodiments 5990, for example as illustrated in FIG. 59,
for femur alignment can include the steps of: rotating the knee
joint 5930 between the first and second points at least two times
where the sensored insert is coupled to a distal end of the femur;
measuring data points 5940 over an arc of the anterior-posterior
axis; and determining 5950 a maximum of the arc. Additional
embodiments, for example as illustrated in FIG. 60, for femur
alignment can include the steps of: calculating a tilt value 6010
of the sensored insert along a medial-lateral line of a distal end
of the femur; and converting the tilt value 6020 to a varus or
valgus number in relation to a mechanical axis of the leg for the
femur.
At least one embodiment is directed to methods and devices for
displaying information to a user to provide information. The
information can have multiple uses, for example provide feedback
for alignment and/or surgery.
For example at least one embodiment is directed to a graphical user
interface (e.g., 100) on an electronic display (e.g., 105, smart
phone screen, electronic screen, tablet screen, touch screen,
projected display, heads-up display), a memory (e.g., RAM, hard
drive, USB removable memory), and one or more processors (e.g.,
single processor, RISC, multiply linked processors such as dual
processors) to execute one or more programs (e.g., the software
system controlling the feedback display) stored in the memory, the
graphical user interface comprising: a portion of an orthopedic
system (e.g., leg, knee joint, hip joint, elbow joint) displayed on
the electronic display; a parameter (e.g., CP rotation, A-P slope,
flexion angle, tibial rotation, tibia angle, medial load on a
sensor, lateral load on a sensor, sensor rotation angle, load
locations) of the orthopedic system displayed on the electronic
display; a portion of an orthopedic insert displayed on the
electronic display; and a parameter of the orthopedic insert
displayed on the electronic display, where in response to detecting
movement of the orthopedic system the displayed portion of the
orthopedic system (e.g., 162) is moved, a change of the parameter
of the orthopedic system is displayed, and a change in parameter of
the orthopedic insert is displayed.
In at least one embodiment the parameter of the orthopedic insert
is a medial contact location displayed as a symbol or area of
contact (e.g., 158A and 158B) on the displayed portion of the
orthopedic insert (e.g., 157). In at least one embodiment the
parameter of the orthopedic insert is a lateral contact location
displayed as a symbol or area of contact on the displayed portion
of the orthopedic insert. In at least one embodiment the parameter
of the orthopedic insert is a medial contact load displayed as a
range on a display (e.g., BB.BB and AA.AA, in FIG. 24). In at least
one embodiment the parameter of the orthopedic insert is a lateral
contact load displayed as a range (e.g., BB.BB and AA.AA, in FIG.
24) on a display.
At least one embodiment further includes the steps of displaying a
dial (e.g., 2900, 3000) that moves in response to movement of the
orthopedic system. The embodiment can change the color (e.g., from
white to blue, yellow to white) of the displayed parameter of the
orthopedic system when the value of the parameter of the orthopedic
system is within a predetermined range (e.g., +/-1 to 3 degrees of
an angular target, +/-1 to 5 mm of a translational location) of a
target value of the parameter of the orthopedic system. At least
one embodiment further includes the steps of changing the color of
the displayed parameter of the orthopedic insert when the value of
the parameter of the orthopedic insert is within a predetermined
range of a target value of the parameter of the orthopedic insert.
Additionally embodiment can change the border (e.g., 3290) around a
value when that value has been fixed.
At least one embodiment can combine the GUI system with the
measurement system. For example at least one embodiment can be
directed to a method of providing feedback of an orthopedic
alignment system coupled to display comprising: displaying a
portion of an orthopedic system on a display; displaying a
parameter of the orthopedic system in the display; displaying a
portion of an orthopedic insert (e.g., a tibia insert) in the
display (e.g., 157); displaying a parameter of the orthopedic
insert in the display (e.g., 154D); detecting movement of the
orthopedic system (e.g., using accelerometers, magnetometers, GPS,
acoustics, mechanical measurements), and moving the displayed
portion of the orthopedic system in response to the movement of the
orthopedic system; detecting a change of the parameter of the
orthopedic insert during movement of the orthopedic system;
detecting a change of the parameter of the orthopedic system during
movement of the orthopedic system; displaying the change in
parameter of the orthopedic insert in the display; and displaying
the change in parameter of the orthopedic system in the
display.
At least one embodiment is directed to measurement of the
anterior-posterior slope/tilt. The measurement can be used, for
example to obtain the A-P slope of a bone cut or of a prosthetic
component (e.g., tibial insert) inserted into an orthopedic system.
The A-P slope can provide user (e.g., a surgeon) information to
determine the prosthetic component has been placed correctly. For
example if, during a knee surgery, all the ligaments are in place
the bone cut would not have any slope. If the PCL were removed, for
example, a supporting post is on the insert and has been found to
require an A-P tilt to allow movement in flexion, thus identifying
the A-P tilt or angle can be important for more accurate fitting of
the prosthetic component.
Thus, for example one embodiment, as illustrated in FIG. 61, can be
directed to a method 6100 of measuring slope or tilt of a prepared
bone surface of a bone comprising the steps of: referencing a
three-axis accelerometer 6110 to a bone landmark (e.g., tibia
crest) when the bone is in extension and where the three-axis
accelerometer is referenced to gravity to measure position and
tilt; placing the bone in extension 6120 as measured by the
three-axis accelerometer; coupling the three-axis accelerometer
6130 to the prepared bone surface; and measuring the slope or tilt
of the tibial prosthetic component with the three-axis
accelerometer. Note that the accelerometer can be calibrated with
respect to a horizontal and vertical reference. The horizontal
reference can be a table top, while the vertical reference can be
perpendicular to the table top. A detailed discussion of
accelerometers is not included since it is well known by one of
ordinary skill in the arts; however U.S. patent application Ser.
No. 13/673,921, "Motion and Orientation Sensing Module or Device
for Positioning of Implants", contains discussion of sensors, bit
and memory discussions, and accelerometers, and the Applications
content is incorporated by reference in its entirety.
Note that measuring the slope or tilt 6140 of the tibial prosthetic
component includes the steps of: measuring the slope or tilt 6150
of the prepared bone surface relative to a bone landmark (e.g.,
tibia crest, mechanical axis); monitoring the slope or tilt 6160 on
a remote system; and storing 6170 (e.g., in computer readable
memory) the measured slope or tilt of the prepared bone
surface.
Additional embodiments, as illustrated in FIG. 62, can further
include the step of changing the slope or tilt 6200 of the
prosthetic component after measurement. Additional embodiments can
further include the step of placing 6210 the three-axis
accelerometer (e.g., where the accelerometer is in a sensor) on a
first reference plane (e.g., a horizontal plane such as a table
top); and measuring 6220 the first reference plane (e.g., recording
a first set of data measured by the accelerometer); reversing a
position 6230 of the three-axis accelerometer on the first
reference plane 180 degrees; measuring 6240 the first reference
plane (e.g., recording a second set of data measured by the
accelerometer); averaging measurements 6250 of the first reference
plane (e.g., averaging the values of the first data set and second
data set); and zeroing 6260 the three-axis accelerometer to
reference to the first reference plane where the first reference
plane corresponds to zero acceleration (e.g., gravity). For example
the first and second data sets can include x, y, z values, and the
averaging step can include averaging all of the x, y, and z values
of both data sets. Then to zero the processor can obtain offset x,
y, and z values to apply to any measurement so that when a sensor
(e.g., with the accelerometer included) lies on the first reference
plane, the x, y, and z values read about zero.
As discussed above additional embodiments can include the step of
zeroing 6270 the three-axis accelerometer to a second reference
plane (e.g. a plane perpendicular of the first plane).
Additional embodiments 6300, as illustrated in FIG. 63, include the
steps of coupling 6310 a sensored insert in a joint of the
muscular-skeletal system where the sensored insert has an articular
surface configured to allow joint movement; and referencing 6320 a
three-axis accelerometer to a tibial ridge (e.g., or tibia crest)
where the tibia is in extension and where the three-axis
accelerometer is used to measure position and tilt.
Additional embodiments 6305 include the steps of inserting 6340 the
sensored insert into the knee joint; placing the leg 6350 in
extension as measured by the three-axis accelerometer; and
measuring the slope or tilt 6360 of the tibial prosthetic component
with the three-axis accelerometer.
Additional embodiments include the steps of placing a shim 6370 on
the sensored insert; and measuring the load applied 6380 by the
muscular-skeletal system to the sensored insert where the loading
on the sensored insert is within a predetermined load range.
Additional embodiments include the steps of referencing the
three-axis accelerometer 6390 further includes a step of placing a
posterior edge of the sensored insert along the tibial ridge where
the three-axis accelerometer is in the sensored insert.
Additional embodiments 6400, illustrating FIG. 64, include the
steps of holding 6410 the sensored insert vertical along the tibial
ridge; monitoring 6420 a vertical position of the sensored insert
on a remote system; referencing the three-axis accelerometer 6430
to the tibial ridge when the sensored insert is within a
predetermined vertical range (e.g., typically +-2 degrees).
Additional embodiments include the steps of referencing the
three-axis accelerometer 6440 to the tibial ridge comprises a step
of measuring a rotation of the sensored insert with the three-axis
accelerometer where the rotation corresponds to a slope or tilt of
the tibial ridge when the leg is in extension.
Additional embodiments, illustrated in FIG. 65, include the steps
of measuring the slope or tilt of the tibial prosthetic component
includes the steps of: measuring the slope or tilt 6510 relative to
the tibial ridge; monitoring the slope or tilt 6520 on a remote
system; and storing the anterior-posterior slope 6530 of the tibial
prosthetic component.
Additional embodiments include the step of changing the
anterior-posterior (A-P) slope or tilt 6540 of the prosthetic
component after measurement.
Additional embodiments include the steps of placing the sensored
insert 6550 on a first reference plane; and measuring 6560 the
first reference plane; reversing 6570 a position of the module on
the first reference plane 180 degrees; measuring 6580 the first
reference plane; averaging 6590 measurements of the first reference
plane; and zeroing 6593 the module to reference to the first
reference plane where the first reference plane corresponds to zero
gravity.
Additional embodiments include the step of zeroing 6595 the
three-axis accelerometer to a second reference plane where the
second reference plane is perpendicular to the first reference
plane.
At least one embodiment, as illustrated in FIG. 66, is directed to
a method 6600 of referencing a three-axis accelerometer to measure
location, tilt, and rotation of the muscular-skeletal system
comprising the steps of: referencing the three-axis accelerometer
6610 to a first plane where the three-axis accelerometer is
referenced to gravity and where the first plane corresponds to zero
gravity; referencing the three-axis accelerometer 6620 to a second
plane where the second plane is perpendicular to the first plane;
referencing a three-axis accelerometer 6630 to a bone landmark of a
bone when the bone is in extension; placing the bone in extension
6640 as measured by the three-axis accelerometer; coupling 6650 the
three-axis accelerometer to a surface of the bone; and measuring
the slope or tilt 6660 of a surface of the bone with the three-axis
accelerometer relative to the bone landmark.
Additional embodiments include the steps of coupling 6670 the
three-axis accelerometer to the bone landmark; monitoring 6680 a
position of the three-axis accelerometer on a remote system
relative to the first or second plane; and referencing 6690 the
three-axis accelerometer to the bone landmark when the three-axis
accelerometer is within a predetermined range of the first or
second plane.
Additional embodiments include the step of measuring 6593 a
rotation of the three-axis accelerometer when placed on the bone
landmark and the bone is in extension. In at least one embodiment
the step of measuring the slope or tilt of the bone surface can
include the steps of: monitoring 6595 the slope or tilt on a remote
system; and storing 6597 the slope or tilt of the bone surface.
Additional embodiments, illustrated in FIG. 67, include the steps
of coupling 6710 the three-axis accelerometer to a first plane;
measuring 6720 the first plane; reversing a position 6730 of the
three-axis accelerometer on the first plane 180 degrees; measuring
6740 the first plane; averaging 6750 measurements of the first
plane; and zeroing 6760 the three-axis accelerometer to reference
to the first plane where the first reference plane corresponds to
zero acceleration (e.g. gravity).
At least one further embodiment is directed to the determination of
the medial-lateral tilt of a bone coupled to a joint. A method of
measuring tilt 8100, as illustrated in FIG. 81, of a prepared bone
surface of a muscular-skeletal joint comprising the steps of:
coupling 8110 a three-axis accelerometer to the prepared bone
surface of a bone where the three-axis accelerometer measures
position and tilt; coupling 8120 the bone to a surface; rotating
8130 the joint between two points where a maximum is located
between the two points and where the joint pivots off of the
surface and where the three-axis accelerometer is referenced to the
surface; identifying 8140 where the three-axis accelerometer is at
the maximum; and calculating 8150 bone tilt.
Additional embodiments, as illustrated in FIG. 82, include the step
of comparing 8210 a location of the maximum to a location of a zero
tilt maximum to determine tilt.
Additional embodiments include the step of rotating 8220 the joint
six times or less between the two points. Note that there is no
limit to the number of times rotating the joint can occur.
Additional embodiments include the steps of: capturing 8230 a
plurality of positions of the three-axis accelerometer as the joint
is moved between a first point to a second point; storing 8240 the
plurality of positions of the three-axis accelerometer with each
movement from the first point to the second point and from the
second point to the first point; and calculating 8250 the maximum
and the position of the maximum.
Additional embodiments include the steps of capturing a plurality
of positions includes a step of measuring 8260 a location of the
three-axis accelerometer with a 15-bit or greater precision.
Additional embodiments include the steps of rotating 8270 the joint
between the two points four times or less.
Additional embodiments, as illustrated in FIG. 83, include the step
of limiting movement 8310 of the joint within a predetermined range
where the maximum is within the predetermined range. For example if
one moves a knee about a pivot point from a medial to a lateral
side along the path the knee is at the zenith location, which in
this non-limiting example would be the maximum.
Additional embodiments include the steps of: maintaining 8320 a
pivot point at a fixed location on the surface; and monitoring 8330
movement of the joint on a remote system where the predetermined
range is shown on the remote system whereby a user maintains
movement of the joint between the predetermined range on the remote
system.
At least one embodiment 8400, as illustrated in FIG. 84, is
directed to a method of measuring medial-lateral tilt of a prepared
bone surface of a knee joint comprising the steps of: coupling 8410
a tibial prosthetic component to a proximal end of a prepared
tibia; placing 8420 a sensored insert into a tibial tray where the
sensored insert includes a three-axis accelerometer to measure
position and tilt and where the knee joint is loaded similar to
final joint loading; rotating 8430 between a first point and a
second point respectively on a medial and a lateral side of the
knee joint where a maximum is located between the first and second
points; identifying 8440 where the three-axis accelerometer is at
the maximum; and calculating 8450 bone tilt. Additional
embodiments, as illustrated in FIG. 85, include the steps of:
referencing 8510 the three-axis accelerometer to a surface;
maintaining 8520 a heel of a leg on the surface; and pivoting 8530
the knee joint off of the heel of the leg. Additional embodiments
include the step of: comparing 8540 a location of the maximum to a
location of a zero tilt maximum to determine tilt. Additional
embodiments include the steps of: rotating 8550 the joint six times
or less between the first point and the second point.
Additional embodiments 8600, as illustrated in FIG. 86, include the
steps of: capturing 8610 a plurality of positions of the three-axis
accelerometer as the knee joint is moved between a first point to a
second point; storing 8620 the plurality of positions of the
three-axis accelerometer with each movement from the first point
and the second point and from the second point to the first point;
and calculating 8630 maximum and the position of the maximum. In
additional embodiments, as illustrated in FIG. 87, the step of
capturing 8710 a plurality of positions includes a step of
measuring a location of the three-axis accelerometer with a 15-bit
or greater precision. Additional embodiments include the step of:
rotating 8720 the joint between the first and second points four
times or less. Additional embodiments, illustrated in FIG. 88,
include the step of: limiting 8810 movement of the joint within a
predetermined range where the maximum is within the predetermined
range. Additional embodiments include the steps of: monitoring 8820
movement of the joint on a remote system where the predetermined
range is shown on the remote system whereby a user maintains
movement of the joint between the predetermined range on the remote
system.
At least one embodiment, as illustrated in FIG. 89, is directed to
a method of measuring medial-lateral tilt of a distal end of a
femur of a knee joint comprising the steps of: coupling 8900 a
sensored insert to a distal end of the femur where the sensored
insert includes a three-axis accelerometer to measure position and
tilt and where the knee joint is loaded similar to final joint
loading; rotating 8910 between a first point and a second point
respectively on a medial and a lateral side of the knee joint where
a maximum is located between the first and second points;
identifying 8920 where the three-axis accelerometer is at the
maximum; and calculating 8930 bone tilt.
Additional embodiments include the steps of: referencing 8940 the
three-axis accelerometer to a surface; and pivoting 8950 the knee
joint off of the femoral head of the femur. Additional embodiments
include the steps of: limiting 8960 movement of the joint within a
predetermined range where the maximum is within the predetermined
range whereby precision increases by reducing the predetermined
range; monitoring 8970 movement of the joint on a remote system
where the predetermined range is shown on the remote system whereby
a user maintains movement of the joint between the predetermined
range on the remote system; capturing 8980 a plurality of positions
of the three-axis accelerometer as the knee joint is moved between
the first and second points; storing 8990 the plurality of
positions of the three-axis accelerometer with each movement from
the first point and the second point and from the second point to
the first point; and calculating 8995 the position of the
maximum.
At least one embodiment is directed to system to support kinetic
assessment, joint modification, and installation of a final
prosthetic joint comprising: a sensing insert configured to measure
load, position of load, and joint alignment; a remote system
coupled to the sensing insert configured to receive measurement
data from the sensing insert where a joint assessment and
subsequent changes to affect load, position of load, and joint
alignment are performed under muscular-skeletal loading whereby a
final joint installation has similar loading, position of load, and
alignment.
Additional embodiments include: at least one articular surface; a
plurality of load sensors underlying the articular surface
configured to measure load and position of load; and a three axis
accelerometer configured to referenced to a table or an
acceleration value where the three axis accelerometer is configured
to measure tilt and location. In at least one embodiment the remote
system is configured to monitor position of load on a display and
where a correction comprising one of rotating a prosthetic
component or soft tissue tensioning can be performed under
muscular-skeletal loading to move position of load on the at least
one articular surface within a predetermined area range.
In at least one embodiment the sensing insert is configured to
measure an offset of a first bone of the joint relative to a
mechanical axis and where the three-axis accelerometer is
configured to provide measurement data to determine the offset of
the first bone. In at least one embodiment the sensing insert is
configured to measure an offset of a second bone relative to a
mechanical axis and where the three-axis accelerometer is
configured to provide measurement data to determine the offset of
the second bone. In at least one embodiment the system is
configured to determine a total offset relative to a mechanical
axis and if the total offset is within a predetermined offset
range.
In at least one embodiment the sensored insert is configured to be
referenced to a first plane, where the sensored insert is
configured to be referenced to a second plane that is perpendicular
to the first plane and where the first plane corresponds to a zero
orientation in that plane or a zeroed acceleration with respect to
that plane.
At least one embodiment 6800, as illustrated in FIG. 68, is
directed to a method of kinetic assessment, joint modification, and
installation of a final prosthetic joint comprising: inserting a
sensored insert 6810 configured to measure load, position of load,
and joint alignment into a joint; transmitting measurement data
6820 from the sensing to a remote system; measuring load 6830 on an
articular surface of the sensored insert; and shimming 6840 the
sensored insert until load is within a predetermined load range;
and measuring 6850 joint alignment under load.
At least one embodiment further includes the steps of: referencing
6860 the sensored insert to a first reference plane where the
sensored insert includes a three-axis accelerometer referenced to
gravity; referencing 6870 the sensored insert to a second reference
plane that is perpendicular to the first plane; and zeroing 6880
the sensored insert such that the first reference plane corresponds
to zero gravity.
At least one embodiment 6900, illustrating FIG. 69, further
includes the steps of: measuring 6910 position of load with a
plurality of load sensors underlying the articular surface; and
adjusting 6920 the position of load within a predetermined area
range. At least one embodiment further includes the steps of:
rotating 6930 a prosthetic component and sensored insert to change
a position of load; monitoring 6940 the position of load on the
remote system; and fixing 6950 the position of the prosthetic
component when the position of load is within the predetermined
area range on the articular surface.
At least one embodiment, as illustrated in FIG. 70, further
includes a step of performing a step of soft tissue tensioning 7010
to change the load applied to the articular surface or to change a
position of load applied to the articular surface. At least one
embodiment, as illustrated in FIG. 71, further includes a step of
measuring 7110 bone slope of a prepared bone surface. At least one
embodiment further includes a step of modifying 7120 the prepared
bone surface to be within a predetermined slope range. At least one
embodiment further includes the steps of: measuring 7130
anterior-posterior slope of the prepared bone surface; and
measuring 7140 the medial-lateral slope of the prepared bone
surface.
At least one embodiment, as illustrated in FIG. 72, further
includes the steps of: measuring 7210 an offset of a first bone of
the joint relative to the mechanical axis where the three-axis
accelerometer is configured to provide measurement data to
determine the offset of the first bone; and measuring 7220 an
offset of a second bone of the joint relative to a mechanical axis
and where the three-axis accelerometer is configured to provide
measurement data to determine the offset of the second bone.
At least one embodiment further includes adjusting joint alignment
7230 within a predetermined alignment range where a joint
assessment and subsequent changes to affect load, position of load,
and joint alignment are performed under muscular-skeletal loading
whereby a final joint installation has similar loading, position of
load, and alignment.
At least one embodiment, as illustrated in FIG. 73, is directed to
a method of kinetic knee assessment for installing a prosthetic
knee joint comprising: inserting 7300 a sensored insert configured
to measure load, position of load, and joint alignment into a knee
joint; transmitting 7310 measurement data from the sensing to a
remote system; measuring 7320 load on at least one articular
surface of the sensored insert; and shimming 7330 the sensored
insert until a load is within a predetermined load range; measuring
7340 the position of load with a plurality of load sensors
underlying at least one articular surface of the sensored insert;
measuring 7350 alignment of a femur and tibia relative to a
mechanical axis of the leg under load with a three-axis
accelerometer within the sensored insert; and monitoring 7360
loading, position of load, and alignment on the remote system.
At least one embodiment further includes the steps of: measuring
7370 an offset of a tibia relative to the mechanical axis under
muscular-skeletal loading; measuring 7380 an offset of a femur
relative to the mechanical axis under muscular-skeletal loading;
and combining 7390 the offsets to determine an alignment relative
to the mechanical axis of the leg. At least one embodiment further
includes a step of measuring 7393 the anterior-posterior slope of a
proximal end of the tibia.
At least one further embodiment is directed to measuring and/or
displaying contact information. The contact information can be
useful since the prosthetic component can be rotated to change the
position of load. Therefore the amount of rotation can be recorded,
displayed and used. In at least one embodiment the contact
information is recorded. Note that contact information can affect
subsequent measurements.
For example at least one embodiment, as illustrating in FIG. 74, is
directed to a method 7405 of adjusting a contact point of a joint
system where a prosthetic component is coupled to a bone comprising
the steps of: placing a sensored insert 7410 in the joint where the
sensored insert has an articular surface, a plurality of load
sensors coupled to the articular surface, and a three-axis
accelerometer to measure position, tilt, and rotation; monitoring
7420 position of load on the articular surface on a remote system
where the sensored insert is configured to send load data to the
remote system; repositioning 7430 the prosthetic component relative
to a bone to change the contact point to the articular surface; and
fixing a position 7440 of the prosthetic component when the
position of load is within a predetermined area range of the
articular surface.
At least one embodiment further includes the step 7450 of changing
a position of the prosthetic component. At least one embodiment
further includes a step of rotating the prosthetic component. At
least one embodiment further includes a step of soft tissue
tensioning 7470 to move the position of load on the articular
surface. At least one embodiment further includes a step of pinning
7460 the prosthetic component to the bone where pinning holds the
prosthetic component to the bone but allows repositioning to change
position of load.
At least one embodiment 7500, as illustrated in FIG. 75, further
includes the steps of: coupling 7510 the sensored insert to the
prosthetic component; positioning 7520 the joint in extension where
the three-axis accelerometer is referenced to gravity and where the
three-axis accelerometer detects when the bone is in extension;
positioning 7530 the prosthetic component or sensored insert to be
aligned to a predetermined location; and zeroing 7540 the
prosthetic component such that the contact point position of the
prosthetic component is zero at the predetermined location.
At least one embodiment, as illustrated in FIG. 76, further
includes a step of aligning 7610 the prosthetic component or
sensored insert to a bone landmark. At least one embodiment further
includes a step of aligning 7620 the prosthetic component or
sensored insert to a mechanical axis of the joint. At least one
embodiment further includes the steps of: rotating 7630 the
prosthetic component to adjust a position of load; monitoring 7640
the position of load on the remote system; fixing 7650 the position
of the prosthetic component when a contact point on the articular
surface is within a predetermined area range; and storing 7660 an
amount of rotation from the predetermined location.
At least one embodiment 7700, as illustrated in FIG. 77, is
directed to a method of adjusting a tibial prosthetic component in
a knee joint comprising the steps of: coupling 7710 a tibial
prosthetic component to a tibia; coupling 7720 a sensored insert to
the tibial prosthetic component where the sensored module has at
least one articular surface, a plurality of pressure sensors
coupled to the articular surface, and a three-axis accelerometer to
measure position and tilt; rotating 7730 the tibial prosthetic
component relative to the tibia; monitoring 7740 position of load
on the articular surface where the sensored insert is configured to
send load data to the remote system; and fixing 7750 a position of
the tibial prosthetic component when a contact point on the
articular surface is within a predetermined area range.
At least one embodiment further includes a step of soft tissue
tensioning 7760 to move the position of load on the articular
surface. At least one embodiment further includes a step of pinning
7770 the tibial prosthetic component to the tibia where pinning
holds the tibial prosthetic component to the tibia but supports
rotation of the tibial prosthetic component.
At least one embodiment, as illustrated in FIG. 78, further
includes the steps of: placing 7810 the sensored insert into a
tibial tray of the tibial prosthetic component; positioning 7820 a
femur and tibia in extension where the three-axis accelerometer is
referenced to gravity and where the three-axis accelerometer
detects when the bone is in extension; positioning 7830 the tibial
prosthetic component or sensored insert to be aligned to a
predetermined location; and zeroing 7840 the tibial prosthetic
component such that the contact point position of the tibial
prosthetic component is about zero at the predetermined
location.
At least one embodiment further includes a step of aligning 7850
the tibial prosthetic component or sensored insert to a bone
landmark. At least one embodiment further includes a step of
aligning 7860 the tibial prosthetic component or sensored insert to
a mechanical axis of the joint.
At least one embodiment further includes a step of storing 7870 an
amount of rotation of the tibial prosthetic component when the
tibial prosthetic component position is fixed.
At least one embodiment 7705, as illustrated in FIG. 79, further
includes the steps of: placing 7910 the sensored insert having a
first articular surface and a second articular surface into the
knee joint where the sensored insert is coupled to a tibial tray of
the tibial prosthetic component; positioning 7920 a femur and tibia
in extension where the three-axis accelerometer detects when the
bone is in extension; positioning 7930 the tibial prosthetic
component or sensored insert to be aligned to a predetermined
location; and zeroing 7940 the prosthetic component such that the
contact point position of the tibial prosthetic component is zero
at the predetermined location.
At least one embodiment further includes the steps of: monitoring
7950 position of load on the first and second articular surfaces;
and rotating 7960 the tibial prosthetic component relative to the
tibia until the position of load of each articular surface is
within a predetermined area range; and measuring 7970 and storing
the rotation required to place the position of load on the first
and second articular surface within the predetermined are
range.
At least one embodiment, as illustrated in FIG. 80, further
includes the steps of: performing soft tissue tensioning 8000;
monitoring 8010 load on the first and second articular surfaces;
and adjusting 8020 loading respectively on the first articular
surface and the second articular surfaces to be within a first
predetermined load range and a second predetermined load range.
At least one embodiment is directed to a system for adjusting
contact position of a muscular-skeletal joint comprising: a
prosthetic component configured to rotate after being coupled to a
bone; a sensored insert having an articular surface where the
sensored insert is configured to couple to the prosthetic
component, where the sensored insert has a plurality of pressure
sensors coupled to the articular surface and a three-axis
accelerometer to measure position and tilt, and where the
three-axis accelerometer is referenced to gravity; a remote system
configured to wirelessly receive position of load data from the
sensored insert where the remote system is configured to display
the articular surface, where the remote system is configured to
display position of applied load to the articular surface, and
where the remote system is configured to store a zero contact point
where the bone and prosthetic component are aligned.
In at least one embodiment the remote system is configured to
display a predetermined area range on the articular surface, where
the remote system is configured to indicate positions of flexion of
the bone, where the remote system is configured to store an amount
of rotation of the prosthetic component relative to the zero
contact point where rotating the prosthetic component changes a
position of applied load to the articular surface.
While the present invention has been described with reference to
particular embodiments, those skilled in the art will recognize
that many changes may be made thereto without departing from the
spirit and scope of the present invention. Each of these
embodiments and obvious variations thereof is contemplated as
falling within the spirit and scope of the claimed invention, which
is set forth in the claims. While the subject matter of the
invention is described with specific examples of embodiments, the
foregoing drawings and descriptions thereof depict only typical
embodiments of the subject matter and are not therefore to be
considered to be limiting of its scope, it is evident that many
alternatives and variations will be apparent to those skilled in
the art. Thus, the description of the invention is merely
descriptive in nature and, thus, variations that do not depart from
the gist of the invention are intended to be within the scope of
the embodiments of the present invention. Such variations are not
to be regarded as a departure from the spirit and scope of the
present invention.
While the present invention has been described with reference to
embodiments, it is to be understood that the invention is not
limited to the disclosed embodiments. The scope of the following
claims is to be accorded the broadest interpretation so as to
encompass all modifications, equivalent structures and functions.
For example, if words such as "orthogonal", "perpendicular" are
used the intended meaning is "substantially orthogonal" and
"substantially perpendicular" respectively. Additionally although
specific numbers may be quoted in the claims, it is intended that a
number close to the one stated is also within the intended scope,
i.e. any stated number (e.g., 90 degrees) should be interpreted to
be "about" the value of the stated number (e.g., about 90
degrees).
As the claims hereinafter reflect, inventive aspects may lie in
less than all features of a single foregoing disclosed embodiment.
Thus, the hereinafter expressed claims are hereby expressly
incorporated into this Detailed Description of the Drawings, with
each claim standing on its own as a separate embodiment of an
invention. Furthermore, while some embodiments described herein
include some but not other features included in other embodiments,
combinations of features of different embodiments are meant to be
within the scope of the invention, and form different embodiments,
as would be understood by those skilled in the art.
* * * * *